Hello, my scappin´friends!

I´m pretty new to Max, but already love it! I have one problem though. I can log in with my user name and password and upload my layouts, no problem. But if I want to log in with my email adress and password to buy something, I will get a message, that my email or password is not valid. Has this occured to anyone else? And what can I do about it?
Looking forward to hearing your ideas!
Greetings from Vienna,
Katharina