So I have a fresh install of UM 23.10. Some of my apps seems like they can't access network, but most of them are working fine. So far Telegram desktop and the Welcome apps are the affected ones. Telegram is a snap app, but other snap apps, like Discord is working perfectly. So it's weird. Any idea?
Does it exhibit that same behavior under 22.04? If no, that would indicate a problem with 23.10. If yes, that would lead me to look into hardware issues (with the machine itself or the network/router. You can test that with another machine.
I didn't try any other version on this machine. Only regular Ubuntu which was 23.10 aswell, and there were no issues with that.
It works under regular Ubuntu and not U-MATE, both at the version 23.10? Is that correct? I would not expect that under under just about any circumstance except a corrupt installation. If you can confirm this with a reinstall of both Ubuntu and U-MATE and document the steps you took to reproduce the problem then I would say that this is a bug and encourage you to report it.
A work around is to see if the LTS version works and use that one. I only use interim versions if I need it such as with newer hardware or app compatibility issues, otherwise it would be for testing.
Best of Luck.