K-9 (on Samsung S9) will send and receive emails on my home WiFi, but not on Data. Other WiFi? *Sometimes*

My emails accounts are on Gmail, and GSuite, so both Google, and I am not sure where to look to track down the issue. I have scrolled through all the K-( options I can find, and not finding an answer there, am starting to think that maybe it is a Google issue.

Any ideas?

Do you get error messages, if so please provide details? Do other apps work in these environments?

Additionally, the following help in figuring things out:

  • K9 release
  • android release
  • pop/imap?
  • incoming/outgoing server configuration details:
    • hostname(s)
    • port(s)
    • security
    • password authentication type

also, with gmail/gsuite - have you set up and are you using app passwords?