not working in new version Nextcloud 19

Support intro

Nextcloud version (eg, 18.0.2):
Operating system and version (eg, Ubuntu 20.04): Armbian 20.02.1 Bionic
Apache or nginx version (eg, Apache 2.4.25): Apache/2.4.29 (Ubuntu)
PHP version (eg, 7.1): PHP 7.4.6
Is this the first time you’ve seen this error? (Y/N): first! On old version 18.0.0…4 this service working

Steps to replicate it:

no steps it just doesn’t work.
always pop up messages what lost connection
what steps should I take to change the situation not working in new version Nextcloud 19

This is an expected result, if you try to use an app which hasn’t been signed-off for Nextcloud 19 yet. The app store shows that the Nextcloud 18 is the latest supported version.

You have to wait until the 3rd-party developer provides a supported version of his app. The missing support problem itself has already been reported as you can see here.