I am using K-9 for an IMAP email account on my Motorola Moto g31(w). It works fine when I am on wi-fi but when out of Wi-Fi range, although all other data services are working fine, I receive no emails whatsoever.
Looking at previous related posts, it is suggested that I “disable connection management” in my Android settings. But I cannot find such a setting to change! I’m using the latest Android 12.
Please, how can I get K-9 to work when not on Wi-Fi?
this is sometimes caused by an IP [numbering] version “mismatch” issue.
when on wifi do you have an ipv4 or v6 (or both) address assignment? when on cell data what do you have? this is generally shown in the device “settings/about phone” item. also, so that we can look to see what it is using, what is the hostname that you have configured as your incoming server?
is better for seeing what your connecting out with as it will show both your private and public IPnumbers. the public number being the relevant one in this context.
my thought was that it was possible, though admittedly unlikely, that either your mobile data connectivity was IPv6 and your provider’s host and your wifi was IPv4 (or potentially the other way around). from your information, it appears that all parties are running IPv4 so that’s not the issue. it could be a routing issue, but you’d have to poke things a bit to be able to prove that. a tool like:
is good for that. a ping or traceroute can be telling.
can you send mail while on mobile data or does being on mobile data impact both sending and receiving? your provider appears to use the same host for both imap. and smtp. (receiving and sending) services. if it’s a connectivity issue then both should be impacted.
When you are on mobile, can you refresh/fetch mails manually? Do you have set pull or push for mail fetching? What error (if any) do you get on mobile when you try to fetch manually?
When I connect to imap.gn.apc.org it announces the STARTTLS capability. It’s possible that your network is using some appliance that tries to downgrade the security of the IMAP connection. It’s also possible that your incoming mail server announces different capabilities depending on where a connection originates. In any case, K-9 Mail refuses to fall back to an unencrypted connection.
You could try changing your incoming server settings to use SSL/TLS.