It's working on development but not on deploy

[baristaGeek]

I did some research and it seemed to be an error with the procfile, but this file is exactly the same as the one this public repository has. Here are the logs:

[ropinotex]

I am experiencing a similar problem: not always, but once in a while I get this 503 error on Heroku. I was not able to trace it back to the source of the problem. I am using flask with Vue.js only in some pages (did not get this error before introducing Vue).
Have you solved it?

[loleg]

It would be helpful if you temporarily enabled full logging and checked Heroku's console again to get the stack trace.

[aliir74]

I am experiencing this error and after some search on net find it that with adding --preload to gunicorn command we can see the full log.
For me that problem was werkzeug version 1. downgrade to 0.16.1 solve my problem.