Contacts sync error

[InfamousUser]

I have calendar sync to Nextcloud set up and working, however when I tried to set up contacts sync I ran into some errors. Upon pressing "Refresh list" the address book list does indeed refresh but I get the following notification:
"Service detection failed Couldn't refresh collection list". This opens up to debug info with HTTP 500 error listed.
The following appears in the Nextcloud server error log:

Info	no app in context NotFound File not found: groups in 'addressbooks'
10 Jan 2026, 23:13:15
	
Info	no app in context NotFound File not found: groups in 'addressbooks'
10 Jan 2026, 23:13:14
	
Error	no app in context ParseError syntax error, unexpected token "readonly", expecting "abstract" or "final" or "class"
Uncaught exception
10 Jan 2026, 23:13:14
	
Error	webdav ParseError syntax error, unexpected token "readonly", expecting "abstract" or "final" or "class"
10 Jan 2026, 23:13:14
	
Info	dav_push No VAPID keys for this nextcloud instance found, generating them now. This should only happen once in the lifetime of the instance!
10 Jan 2026, 23:13:14

Do I have something configured wrong or is this an app bug?

[rfc2822]

HTTP 500 indicates a server problem.

unexpected token "readonly", expecting "abstract" or "final" or "class" could be a hint for a wrong PHP version. Please make sure that your server is working (you can also test with other CalDAV/CardDAV clients), the PHP version is up-to-date and the database is OK.

[InfamousUser]

Coincidentally I was just doing maintenance and updated PHP - it was on 8.1 - which is deprecated but supported, but someone must've mistaken supported with unsupported because it seems to have resolved this. I will do some more checks to verify.

[InfamousUser]

Yep that fixed that, got some other issues now but this is solved. Thanks a lot!