Hey, I am having an issue with this error: Invalid credentials error on fetch from IMAP
I use a dedicated Gmail account and have for a very long time with this plugin (pretty much since you introduced the feature). I last used it in early January of 2020 but today I keep getting the error. I found
This Bug and it looks similar and I tried all the steps you mentioned there but my issue seems different.
For some reason, my "Less Secure Apps" keeps turning itself off after an hour or so. When it was enabled, I was able to access the account via the plugin, and it marked all but two of the unread emails as read (as it scrapped the URLs) but then the error still popped up. I had to enable it several time and I got several security alert emails which I said were me. I have only been trying today so maybe it is a google issue? It finally worked too after about 20 tries. But I wanted to send the bug here for you so you could see it regardless. Perhaps it was a quantity issue? I had about 250 email alerts unread, mostly AO3 but some FFN and others.
Thanks for all your hard work on the plugin, it's my most used in Calibre, for sure!