Adding endpoint to lora-app-server api

I am trying modify lora-app-server to add new endpoint.
For that:

  1. created message.proto custom proto in api folder
  2. this proto file added to api/
  3. then it compiled by $ make api which generates api/message.pb.go, api/ and api/swagger/message.swagger.json
  4. internal/api/external/message.go implemented as well as internal/storage/message.go
  5. js files of ui modified to call endpoint /api/messages registered in api/message.proto file.
  6. new server registered:
    api.RegisterMessageServiceServer(grpcServer, NewMessageAPI(validator))
    in setupAPI() function of internal/api/external/external.go file.

So when I open web interface of lora-app-server I see that request for url http://localhost:8078/api/messages?limit=10&applicationID=1
returns 404 and no log messages of backend at all.

Along with 404 error I get following error message:

When I add this endpoint to existing proto file everything works as expected. But no luck in separate proto file. Did I miss something?

I want to implement custom endpoints using separate proto file to stay compatible with feature updates of lora-App-Server.