====== NextCloud 27.0.0. Use system cron service to call the cron.php file every 5 minutes. Recommended for all instances. The cron.php needs to be executed by the system user "www-data". ====== 


Above is the entire warning message in the Administrative -- Overview section of NextCloud.

===== [Solved] Change from Cron Service to Ajax =====

Select the correct radio button within nextcloud administration.

This eliminates the entire Cron problem without any additional configuration.

The Ajax service runs the job every time a user accesses a page of NextCloud.