diff --git a/api/v1/openapi.yaml b/api/v1/openapi.yaml
index c5e3508..226614e 100644
--- a/api/v1/openapi.yaml
+++ b/api/v1/openapi.yaml
@@ -34,7 +34,7 @@ paths:
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
     post:
@@ -58,13 +58,13 @@ paths:
         "400":
           description: Invalid input
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
   /trainings/{trainingID}:
@@ -93,13 +93,13 @@ paths:
         "404":
           description: Training not found
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
     put:
@@ -133,19 +133,19 @@ paths:
         "404":
           description: Training not found
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "400":
           description: Invalid input
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -170,13 +170,13 @@ paths:
         "404":
           description: Training not found
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -208,7 +208,7 @@ paths:
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -243,13 +243,13 @@ paths:
         "409":
           description: Date already exists
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -284,13 +284,13 @@ paths:
         "404":
           description: Date not found
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
     put:
@@ -327,25 +327,25 @@ paths:
         "200":
           description: Date updated
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/TrainingDate"
         "404":
           description: Date not found
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "400":
           description: Invalid input
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -386,7 +386,7 @@ paths:
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -424,13 +424,13 @@ paths:
         "409":
           description: Attendee already exists (attendee already registered for this date)
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -474,13 +474,13 @@ paths:
         "404":
           description: Attendee not found
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -534,13 +534,13 @@ paths:
         "409":
           description: Feedback already submitted
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -581,7 +581,7 @@ paths:
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -613,7 +613,7 @@ paths:
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 
@@ -660,7 +660,7 @@ paths:
         "500":
           description: Internal error
           content:
-            application/json:
+            application/problem+json:
               schema:
                 $ref: "#/components/schemas/ProblemDetails"
 components:
diff --git a/internal/api/api.gen.go b/internal/api/api.gen.go
index acd2052..2c74a7e 100644
--- a/internal/api/api.gen.go
+++ b/internal/api/api.gen.go
@@ -599,39 +599,39 @@ func RegisterHandlersWithOptions(router fiber.Router, si ServerInterface, option
 // Base64 encoded, gzipped, json marshaled Swagger object
 var swaggerSpec = []string{
 
-	"H4sIAAAAAAAC/+xbzXLjuBF+FRSSQ1JFi/LOpHaiU7zrZOPKJnGt7RwymUOLbEqYIQEOANqjculJcsq7",
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-	"EjQT3PxOhMxA0xllXL/5hgZUr3J0l7hASdcBTZEv9LLnYA4ZmqHlE6WlUWEd0FyyCLd1iYTMhQRtH/1a",
-	"YkJn9FfhZl9huanw0s5fB1TkyHsOXnsNxfwjRtrekfi5YBJjOnvvtA02gFRqftiaGNQhPS/1bW0FcoiY",
-	"XvVEKi6F+KH2RrCNXAwr1ddUIvKW/boF+iFXx6lUze+wElYqV1u4B3JnWiOPsQNBzIClnbp/hVbd5nRi",
-	"dmjyJ8R4DtGnbS2AC77KROF8BRMoUk1nCaQKvci5ECkCNzIjkWXIdafaTF0twVycpam4M0r2kWjI6Px2",
-	"y+QZfGFZkdHZ6TSgGePuYrrNhRYypciNtl3oXHa7KGSicPvz6iSpAE07NeBFNndkjAopkUfWH5CbUe/p",
-	"9//8Cw3oH29+ogG9uTqvqVEzaYdiYp5ido4aWFqaRUWS5Y7r9MqSl+glaBKBlAwV0UsksZtAREKAE5RS",
-	"SMK4+f3n6+tLIlHlgiuckCtEstQ6V7MwjEGDlhB9QjlhqJOJkIswFlG41FkayiT69t30W5IISTIhkTDu",
-	"UGGCT/7lIkgj1loVtlU+I8siA34iEWKYp0jwS54Ct3KIyjFiCYuIFkQvmSIiKsFEsxeztdxBMukKGIwr",
-	"DdyZsr3qzU8XRGKCTphFjMXINUsq0PziwxZVGnTRYZvrJTq03QASiRjJAjmaoB+T+cpKFpItGCcK5S1K",
-	"C27vfdfCn2Y6xR5YqyLLQK5aMokR2Lk3d+MxYO4Q3fJS+7Tahoc0qEhUs2yX+9YTPqTp3xM6e/9wsK9X",
-	"Ceug7fcsbvh8UbB4awcB/XKyECflTV0Km1yc15+csCwX0kaQHEwlQRdMpzCfZCBRLT9PIpGFy8+hCcci",
-	"SViEtZ8nkLMw/7QItde0DRuLO/D4UEOkyteDUbETt5GBOJaoVHfIfzxqZrURIlfP149C0AvYRtJMBr7a",
-	"N5LViiNDs15zDEbST96rp1ZSR4HU2iavRDhmcA2RrpWFlEH2h1vxUWO0tHoYLWhVG9J/iI/6v/+OluSv",
-	"IPF//6EBLaSZVeX1u7u7ydZsUzOzCLmy7C4lXUqRS4Ya5KqWVeh3fofk7PKCBvQWpXKp4HTyZjKtmhPI",
-	"GZ3RN5PTydSUA6CX1kgeDnu1QLs1Y0Wb8y9iOqM/MqWv/SgDmStQ7IxvptMKl7LchDxPmau7w4/KVf2O",
-	"OJYUGjO1q9yvhf/KHCAlrJzJ2vkuZUrbpOl1XAf0dwP1erj7aBR6HUpccI2SQ+qqOZtBy2xe4kcgTWsK",
-	"BlSDQfw93dwzLpkL1WGA7yWCRg+KIy0q/Z2IV3vbZCPrNj1DywLXW3Y/3dvSzXVbhVr5jEQWhNjY9u2B",
-	"bXsLKYsJ43mhR0YtxwwChOOdp9dX2LUOas4eFnkkMsYXJ6aJftj3b8qh9eSpbAyRkKFGqWzCYEbbzwXK",
-	"1Sb6JdLGwg0WO44VTBLpkqPFPqSkLGO6Ich3vaZx3SX1w75CX6sX63HM1Kr8vF0HeFZHad4/tDqSjDSs",
-	"VlR2Wtq2ekewLffT9on76ufF+dqxI0Vnm6ZTnNv7tXjc5Qm2QtkQ2Eum7cjaSewxtTXbvH/b0VB7aC04",
-	"ZZx+e0CyeA240CQRBY9HRlhHGwKemmS+ItZ43cVAZ0D+AfUrJt70IDXH2SaVHlncZvEPqPtT2FRMWxS+",
-	"yWN4beFzBPX69LD1emGtPIZ6/ejADQd27tfXh79eIYW7O4c+HcMxXT3qaMR3Ar+MGn5Tuj/Uxvq6vd9J",
-	"ybnr447p5WnpxVHtZY6ENms3WWXuN4+Efn9ATtvVIZUI8YrgF6a0GvPBkI33iZA9nWtXyA/vY/uX0IAe",
-	"+VV4YtC5o7j6+2zPuznE33K9On/rDC/W9dvVR9/xWw8ckt12901Hl/r5utRI0vX0sOn6tXaEow5Rvhsc",
-	"FqJ61wghlC899O8Uz/yMY3j7+VcMz9wD197iGdALb0g50n7YK+hccoBz1vY2pE/2OB7M556N/odKshvq",
-	"vVxv3NShRffy2cv1yV6DZq9MfgPtBxIXTGmUGG9eszVE+O3IHPQsjglw72NEiyd45yOSaHgP/iXCgf33",
-	"4T38mFWfdUdQf510z7s61KuqvU4YfBh5sVMGr8HYTxpqoelJhcNTQ1OY1D9kGliD+HeKj5HqGKlGFame",
-	"tabcvEr/MvVkc/1m8KmevVwt6TWoSkZVzDOmS11GFIqvrF6kCoDuj5fHxWU/x0fTIZG5HoJ7Hbwc4+7x",
-	"3GVYoBhy5pLUZo3xyMU77PM56CCPfDXeeOTunrk7mLFGqP3G2fGrqcGPIoKUxHiLqcgz5Lr8HrrxKdss",
-	"DFMzbimUnr2bvpuGt6f2k8DWJ/EaFkaLDglqFoaQs8mGLBPlRjeY1Sn2Uoq4iNxH6r0ktyV+WP8/AAD/",
-	"/yD5hI62RAAA",
+	"H4sIAAAAAAAC/+xbzXLbuhV+FQzaRTulRfkmnZtqVd/r9tbT29YT2100zeKIOJSQkAADgHY0Hj1JV32X",
+	"9r06AEiIohiLdGRLbrQTSeDg4Dvf+YPIe5rIvJAChdF0ck91Mscc3M+/4t21Ai64mNnLQskCleHoHrJS",
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+	"TOmE/iJe7SuuNhVfuvnLiMoCRc/By6ChnH7AxLg7Cj+VXCGjk3de22gFSK3m+42JURPS80rf1laggISb",
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+	"0eSPiGwKycdNLUBIschl6X0FUygzQycpZBqDyKmUGYKwMhOZ5yhMp9pcX83BXpxlmbyzSvaRaMno/XbD",
+	"5Dl85nmZ08npOKI5F/5ivMmFFjKVyJW2Xehcdrso5LL0+wvqpJkEQzs1EGU+9WRMSqVQJM4fUNhR7+iP",
+	"//gzjegfbt7SiN5cnTfUaJi0QzE5zTA/RwM8q8yiE8ULz3V65chLzBwMSUApjpqYORLmJxCZEhAElZKK",
+	"cGF//+n6+pIo1IUUGkfkCpHMjSn0JI4ZGDAKko+oRhxNOpJqFjOZxHOTZ7FKk+/fjL8nqVQklwoJFx4V",
+	"LsXonz6CrMVap8KmymdkXuYgThQCg2mGBD8XGQgnh+gCE57yhBhJzJxrIpMKTLR7sVsrPCSjroDBhTYg",
+	"vCnbq968vSAKU/TCHGKcoTA8rUELiw9bVBswZYdtrufo0fYDSCIZkhkKtEGfkenCSZaKz7ggGtUtKgdu",
+	"7303wp/hJsMeWOsyz0EtWjKJFdi5N3/jMWBuEd3yUve03kaANKpJ1LBsl/s2Ez5k2d9SOnn3cLBvVgnL",
+	"qO33nK35fFlytrGDiH4+mcmT6qaphI0uzptPTnheSOUiSAG2kqAzbjKYjnJQqOefRonM4/mn2IZjmaY8",
+	"wcbPEyh4XHycxSZo2oaNsw483jcQqfP1YFTcxE1kgDGFWneH/MejZlc7QOSa+fpRCAYBm0jaySAWu0ay",
+	"XvHA0GzWHIORDJN36qm11INAaumSVyo9M4SBxDTKQsoh//2t/GAwmTs9rBa0rg3p3+UH859/JXPyF1D4",
+	"33/TiJbKzqrz+t3d3Whjtq2ZeYJCO3ZXki6VLBRHA2rRyCr0h7BDcnZ5QSN6i0r7VHA6ejUa180JFJxO",
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+	"hcFcbyv3G+G/NgcoBQtvsna+y7g2LmkGHZcR/e2DelUJ8Deb+j3chawVfB3KXAiDSkDmqzqXSausXuFI",
+	"IMsaikbUgEX+HV3ds65ZSN1hiB8VgsEAjicvavODZItBRuidfdc9xKgSlxv2P93Z0uvrtgq26hlJHAjM",
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+	"W2FtUPqmYPCthdcDqPPHz1vnl87Kh1TnHx37Qcf2btnXt79cWcXbO48+HccxrT3qyCV0Ev9fPcCq9H+o",
+	"HQ51f78TmHPfDx7Tz9elH0+5/Rw1rdZeZ5W9v37U9Ls9cNtpAZlCYAuCn7k2+iUcOLk8kErV09m2pYL4",
+	"nrm/oAb03N+EZ0adO2L133U73s1z/A3Y6yTBOcXeTxGcFi/mBMF55JDst73vOrrYy3WxA0nnu/eXXmn9",
+	"2Fm+oBAWusphIax3TRFD9VJG/47zLMw4hr+XX2E8cS/deMtoQE+9IuWB99VBUe+aA5y0scch/XbA89l8",
+	"78nc4LmS8YqC++ux13Vo0b56tv9+O2iy3nOTX0H7gcIZ1wYVstVrwZYQvz5Qhz1jjIAIPkeM/ApvfURy",
+	"je8hvPw4sI9/fo8/Ztsn3RE0X4Pd8a6e6xXbXicVIZzs/bQiaPJSTiwaoeqrCouvDVVx2vwga2CNEt6N",
+	"PkauY+Q6qMj1pDXn6pOA/dSb6+uvB5/62f5rzaBJXVLqcppzU+l0gKH5yulH6oDo/+B5XJwOc0J0HRKp",
+	"myG514HNMQ4fz2uGBY4hZzVpY9YhH9UEx306Rx3kmd+MVx45/EQcHsxcK9R9y+15tq7BzzKBjDC8xUwW",
+	"OQpTffe99sneJI4zO24utZm8Gb8Zx7en7tPH1qf/BmZWiw4JehLHUPDRijQj7UevMaxT7KWSrEz8x/i9",
+	"JLclvl/+LwAA//9BeUHGnkUAAA==",
 }
 
 // GetSwagger returns the content of the embedded swagger specification file