Nexcloud Snap Installation Problems

I have two problems after installing Nextcloud for Ubuntu 18.04 (not server) via the snap package (I followed this instructions). I am running Nextcloud on a MSI cubi.

The first problem is that Nextcloud isn’t reachable after I reboot my system. Even though I disabled and enabled apache and mysql it says “Site isn’t reachable”

The second problem is that if I don’t reboot my system Nextcloud becomes unavailable over time. I set everything up yesterday and it has been working fine but today it says “Site not reachable”

I hope somebody can help me.