If you get the error 'No permission to create web service token for the service local_mobile' when logging in to the Moodle app, then it is likely that you need to change a permission for the 'Authenticated User'.
The permission for 'authenticated user' -> moodle/webservice:createtoken needs to be set to 'allow' before users can login.
To change the setting:
- go to Administration> Site administration> Users> Permissions> Define roles
- click on the 'edit' icon for the 'Authenticate User' role (in the 'Edit' column at the end of the row)
- in the 'Filter' box (under the 3 large boxes) type in 'moodle/webservice:createtoken' (tip: DON'T hit the enter key!)
- click on 'Allow' for the Create a web service token setting
- 'Save changes'