[Bug]: Server 31.0.4 CalDAV and iOS 18.4.1 Username with "@" leads to login/sync failure

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

IPhone/Ipad tries to sync calendar with right credentials.
As I see, iOS converts the user-name test@google.de to test%40google.de
This user-name is not accepted by nextcloud server.

Steps to reproduce

Try iOS caldav with a username that contains @ like an email-adress.
2.
3.

Expected behavior

I'd expect that syncing the calendar works like in NextCloud 30.x

Nextcloud Server version

31

Operating system

Other

PHP engine version

PHP 8.3

Web server

Nginx

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

Fresh Nextcloud Server install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

No response