I\'m having problems on sandbox.paypal.com login with my test accounts since they\'ve changed the interface.
I was forced to create a new account on developer.paypal
Once you validate and log in using your PayPal credentials, you can import your individual sandbox profiles. Prior to logging in to a specific sandbox account, you will have to clear your browser cache and cookies. I was having the same issue with both Chrome and Firefox. After clearing cache/cookies, I was able to log into to a sandbox profile without any issues.
If you do not clear C&C, you will receive the following error:
"This Sandbox email address is not available. Please enter another email address."
Thanks,