Environment Setup and Configuration Moodle 3.4 thru 3.10 OS: CentOS 7 PHP: 7.2 Curl: 7.76.1 city-fan.org Enable web services for mobile devices in Moodle If not already, log into Moodle as an Administrator Click  Home  >  Site administration  > Mobile app > Mobile settings Activate the checkbox for Enable web services for mobile devices . Reproducing and testing the Issue Login to Moodle as an Administrator. Click  Home  >  Site administration  > Mobile app > Mobile settings ISSUE :  The message " It seems that the HTTPS certificate for the site has expired. " will appear but the certificate is not expired. A debug on the variable  $cert  in the function get_potential_config_issues from the file /admin/tool/mobile/classes/api.php  will reveal that the key ['Expire date'] is written with uppercase (Expire Date) and not with lowercase (Expire date) like it appears on the file. This causes the array to return Null and to show the above warning message. A possible solution would be to check if the both key names are present (lowercase and uppercase). Let me know if you have any questions. Best regards, Ovidiu