lbchv
lbchv
+1 faced with the same issue, nothing in the logs
I noticed that this issue appears when we deploy our app and celery service restarts 
Issue is reproduced in the following case: 1. reach flower max_tasks (by default 10000) 2. restart celery
@VitalyKrivoshapkin thx, i've adopted your changes https://github.com/sciyoshi/redmine-slack/pull/132 resolve this issue