We are facing an issue like below. I already tired purge all cache but it gaves same error. If i try purge cache one by one only Moodle MUC Cache gave an error. This error shows up while deleting a user.
Default exception handler: Coding error detected, it must be fixed by a programmer: The data source class does not exist. Debug:
* line 506 of cacheclassesdefinition.php: coding_exception thrown
* line 324 of cacheclasseshelper.php: call to cache_definition::load()
* line 866 of courseclassescategory.php: call to cache_helper::purge_by_event()
* line 1578 of libaccesslib.php: call to core_course_category::role_assignment_changed()
* line 2036 of libenrollib.php: call to role_assign()
* line 158 of enrolmanualajax.php: call to enrol_plugin->enrol_user()