It seems, that there are also other people who are running into this bug.
Email Read IMAP Node works sometimes - Questions - n8n
Because I can not find any other logs and it seems that nobody knows if there are other logs I’m wondering if it is a mail provider related problem. If that’s true, perhaps anybody can recommend a working mail provider. Sounds a little bit unrealistic to me that it’s not working with gmail but with another one but you never know 