I’m using mattermost 5.4.0 and mattermost app 1.13.0 on android (latest releases) and i have exactly the same issue: when i activate TLS and i use a certificate released by let’s encrypt and manually added to configuration (setting use let’s encrypt:false) i can connect with a PC to mattermost server but app doesn’t work.
I have made several tries, with and without nginx server and using the APP the issue is present either on direct mattermost server and through the proxy.
Another interesting thing is that the app work well on first connection until i change android app. When i reopen mattermost app the issue happen and the “Can’t connect, please verify the URL and your internet connection” error appears. if i reboot the android phone nothing changes.
Another really strange thing is this:
if i make a logout on the app i can’t pass the first address and connection step but i have found a strange workaround: i have to close the app, i have to set https://demo.mattermost.com, click on connect reaching username and password windows, now i have to go back setting my mattermost server address where i put my (https) server address and magically i can pass over the connect issue, set username and password and access to public channel and it work and i can send a message.
When i’m in also push notification works.
My actual configuration is:
This is our config:
Nginx active with “standard” configuration
let’s encrypt certificate manually generated and set (no automatic generation or renew)
both http and https active, with automatic redirect to https.
other parameters set as indicated on mattermost web user guide.
It seems that newer version of mattermost app and server doesn’t solve the issue.
thankyou to all