Hi Juan, I have the same problem.
after trying everything and lose many hours I am not able to connect to Moodle through the official App.
My Moodle version is 2.6.5. I'm the administrator.
Web services enabled
Local Mobile Plugin Moodle additional features installed and enabled.
The token cards for the administrator activated
Protocols REST and XML-RPC activated
On activation ID Web Services ('Web Services')
I tried the test client and Web services continues error.
The app tells me check the URL or use 2.4 or higher. All it checked and nothing.
I do not know what else to do.
Can I send you one USER + PASSWORD? There must be an administrator account?
Thanks in advance