Cannot connect to external calendars integrated in NC

Hello everyone,
I added some external calendars to Nextcloud and want to distribute them via my NC Server. But now I cannot access them. Tested with Thunderbird and DAVx5 on Android. Am i missing something here?

Thanks in advance for your kind help!

In DAVx⁵ calendar subscriptions show up in the “Webcal” tab and require the ICSx⁵ app to setup.

Thunderbird with Lightning doesn’t support accessing subscriptions exposed through CalDAV, so you’ll have to add them manually. Maybe the TBSync Thunderbird addon can help with this, never tried.