The most recent change in POP3 polling happened in January.
https://github.com/discourse/discourse/commit/5710d5d771537d106fbe3488355ded00e514c073
That alone shouldn’t stop Discourse from polling, but it’s possible that an incoming email raises an exception. There’s no error handling in the new code…
@jzedlitz Are you still seeing the problem and want to help get to the bottom of this? Are there any related errors in /logs? Do you see an error in /sidekiq/scheduler when you search for Jobs::PollMailbox? Do you see an error when you manually poll in the rails console?
./launcher enter app
rails c
Jobs::PollMailbox.new.execute({})