I'm now unable to use MarsEdit with Blogger on Mojave or High Sierra. When Google asks me to authenticate instead of getting the usual embedded web page for entering credentials I get a blank page.
Either Google has changed something so this only works on Catalina or there's something odd about my Google accounts. I've tested with
- two non-2FA Google Apps identities that used to work
- my personal 2FA Gmail Google ID
- my wife's personal Gmail Google ID never used for blogger
- two user accounts on my Mojave machine
- 1 user account on High Sierra
- Admin and non-admin account
- Clearing caches with Onyx
- I think I also tried an older version of MarsEdit that was on my old account on the High Sierra machine
Update 12/6/2019: I eventually realized the problem was my home network. I have a Comcast Xfinity router and an Apple AirPort Extreme. Both have had no configuration changes in months, but Comcast recently updated my service and the AirPort firmware went to version 7.9.1 a few months ago.