While using SBIE 5.31.6 the OAuth option in IMAP within Pop Peeper works as expected. Upon updating to 5.33.1 (which happens to fix authentication issues in firefox alongside MS accounts eg outlook) suddenly OAuth no longer functions in Pop Peeper (perhaps elsewhere as well?) and it can never retrieve mail.
Side Note: Switching over to passwords works with 5.33.1.
It seems highly likely that this could be related to the recent (auth/rpc) changes in SBIE but what does my drunk @$$ know?
I simply reproduced an issue a friend had asked me to look into. I don't normally use email software nor am I familiar with OAuth or Pop Peeper! However the same issue starts for both of us using the latest versions of SBIE & Pop Peeper on a gmail account using oauth. He tested on Win 8.1 x64, me on a Win 10 x64 VM
(Main installer)
https://data.esumsoft.com/download/POPPeeperPro-Install.exe
(Plugin for SSL [among others], don't know why SSL isn't already an included standard these days.... /cough @ silly that dev)
https://data.esumsoft.com/files/POPPeeper_WebInstall-Plugins.exe
I don't currently use SBIE or Pop Peeper but if this is anything close to what I fear it may be [eg a broader issue with oauth] related to the changes made to enable ms outlook on FF, etc now seems the best time to nip it in the bud.
Note that you want to keep an eye out for a small yellow ! in the bottom right corner of Pop Peeper to click on and open the error message(s) as they don't seem to simply pop up as one might originally expect.