Why am I seeing a HTTP 501 Not Implemented error notification?

Some users are getting an HTTP 501 Not Implemented error, as shown in the screenshot below. It is caused due to the Recently contacted feature of Nextcloud.

How can I get rid of this Error?

This functionality is already disabled on murena.io, and the local address book removed on /e/OS 1.0 and later.

If you are a user of a version lower than /e/OS 1.0.0 (typically based on Android 9 or earlier), please follow this guide to remove this address book manually from your phone.

Steps for manual deactivation:

1. Open system settings

2. Go to the Accounts section

3. Tap Recently Contacted and Turn off the toggle

Congrats! Now, the recently contacted error notification will not bother you again.