It seemed has helped me for pretty stable SMS tx, by have the most current config. In my case for Telekom .de , and brands using it, e.g. Pennymobil .de …, etc. I have recognized with SIM by Pennymobil .de I can use the Telekom .de config: Data-AP as internet.v6.telekom /dual while MMS-AP only work with internet.telekom, (IPv4 only) on proxy 109.237.176.193:8008 maybe that is in use for SMS too?
To use this I need developer mode activation?
Yes. Or ssh access at least.
Thank you all for the fix for the case. I was baffled when a SMS got stuck and suddenly “nothing” worked anymore… I saw the behaviour with systemctl and journalctl but it would have taken a while for me to find the problem !