Created attachment 120099 [details]
Error message upon testing the connection

SUMMARY
KOrganizer does not seem to communicate passwords containing certain non-ASCII characters correctly when communicating to a CalDAV server. In this case, a stable Nextcloud instance was used.

STEPS TO REPRODUCE
1. Add Calendar
2. Select "DAV groupware resource"
3. Fill in the username
4. Type in a password with certain non-ASCII characters, like 'ö', select "Next"
5. In "Use one of those servers" select "Nextcloud"
6. Fill in the correct host data
7. On the next dialog, click the "Test Connection" button

OBSERVED RESULT
Upon testing the connection, the error with the following error message occurs: "An error occurred: There was a problem with the request. Invalid username/password (401)."

EXPECTED RESULT
The login data should be accepted.

SOFTWARE/OS VERSIONS
Linux kernel: 5.1.2
KOrganizer: 5.11.1
KDE Plasma Version: 5.15-1
KDE Frameworks Version: 5.58.0
Qt Version: 5.12.3 (built against 5.12.3)
Nextcloud: 15.0.7
All versions are the latest available versions.

ADDITIONAL INFORMATION
Using a password only containing ASCII characters works as expected. The password has been copied, pasted, and checked for errors.