Might be worth you raising a case in your org's secret support group where it will get picked up quicker.
Were you recently upgraded to Jive 7?
How did you access mobile before?
Couple things it might be:
- Mobile Gateway was removed in the new Mobile v3
- Your community uses SAML SSO and that is not working correctly
- When you were upgraded they didn't configure the the mobile module
- They have oAuth turned on still
You will need to open a case for this one. Let us know what they find out!