As admin, enable "Mobile services": Site administration ► Mobile app ► Mobile settings Create a Token in the mobile app service for any user in the site (not an admin account) Click on Site administration ► Plugins ► Web services ► Manage tokens Open the console an execute this new curl request, replacing wstoken with the token you just created and the site url with yours. curl 'http://localhost/m/stable_master/webservice/rest/server.php?moodlewsrestformat=json' --data 'wsfunction=core_webservice_get_site_info&wstoken=3af67232a7596ceb658df4db329e5ad6' | python -m "json.tool" And check that the returned advancedfeatures -> messagingallusers field value is set to the same value that the global setting that can be found at "Site administration -> Advanced features" (If the setting is checked, the value returned will be 1, if is not checked the value returned will be 0)