Wiki.js on Heroku: H12 Request timeout error socket.io

Actual behavior
I deployed a Wiki.js on Heroku: https://github.com/Requarks/wiki-heroku It works but after short time I start getting Application Error with following error:

2018-10-30T14:25:00.953972+00:00 app[web.1]: 2018-10-30T14:25:00.953Z - info: [AGENT] Running all jobs...
2018-10-30T14:25:00.958496+00:00 app[web.1]: 2018-10-30T14:25:00.958Z - info: [AGENT] Performing pull from remote Git repository...
2018-10-30T14:25:02.383893+00:00 app[web.1]: 2018-10-30T14:25:02.383Z - info: [AGENT] Git Pull completed.
2018-10-30T14:25:02.401264+00:00 app[web.1]: 2018-10-30T14:25:02.401Z - info: [AGENT] Git Push skipped. Repository is already in sync.
2018-10-30T14:25:02.442099+00:00 app[web.1]: 2018-10-30T14:25:02.441Z - info: [AGENT] All jobs completed successfully! Going to sleep for now.
2018-10-30T14:25:18.063506+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5NDTq" host=example.com request_id=a2f652c7-72ba-4f21-b743-4635d3f38d0a fwd="12.34.567.89" dyno=web.1 connect=1ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:25:48.164886+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5NKq5" host=example.com request_id=9cf9948e-5e1e-4745-920f-6af266aa4c6a fwd="12.34.567.89" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:26:22.746359+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5NTFP" host=example.com request_id=a1ffa606-6bdb-438f-b6ef-7726576ca9d6 fwd="12.34.567.89" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:26:58.916409+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5Nc5Y" host=example.com request_id=6ab44782-3675-4ed7-b5b4-008e9f883db6 fwd="12.34.567.89" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:27:34.286419+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5Nkhy" host=example.com request_id=db9a8a0f-1697-4659-9b57-05f977082571 fwd="12.34.567.89" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:28:04.180689+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5Ns19" host=example.com request_id=c068d320-1e56-492f-bbad-05bc144fca92 fwd="12.34.567.89" dyno=web.1 connect=1ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:28:38.458974+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5N-O9" host=example.com request_id=85574f32-87c9-45f2-b0dc-89cffdc44eb1 fwd="12.34.567.89" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:29:05.255146+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5O4xU" host=example.com request_id=08662c7a-458a-443d-a069-6df762da83f7 fwd="12.34.567.89" dyno=web.1 connect=1ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:29:32.430640+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5OBaD" host=example.com request_id=efc74d16-96c2-4882-b067-c60a8ba8fd3e fwd="12.34.567.89" dyno=web.1 connect=1ms service=30000ms status=503 bytes=0 protocol=http
2018-10-30T14:29:59.482605+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path= "/socket.io/?EIO= 3&transport= polling&t=MR5OI9-" host=example.com request_id=9c0e05b3-d1ef-4ddf-9480-02f6710cc0b9 fwd="12.34.567.89" dyno=web.1 connect=0ms service=30000ms status=503 bytes=0 protocol=http

The only way to get it work again is to restart all my dynos.

Any suggestion about what is causing that issue and how to solve it?

Thanks