Hi @LizBoamah 

Welcome to our o2 Community. Great news and fully appreciated that you are using the Mein o2 App \o/

I cannot log in to my meine o2 app its give me error has occurred and to try again but it does not work. How do i fix this 

Often a re-install fixes this problem, so my advise is:

First deinstall the app and then install it for a new try, in most times the apps works fine after this procedere.

Best regards.