I'm having the same issue.
I logged out of the app and then kept getting errors about incorrect username and password when attempting to log back in. I deleted and reinstalled the app and can still not log in.
I called Tesla in Brooklyn they were initially not very helpful: "you need to reset your password, sir!!"
but then when I explained to them (for the 3rd time) that I was able to access the MyTesla page on my desktop without issue, they relented and said they are having connectivity issues.
they asked me to "call back tomorrow"
but at least I know it's not a problem on my end.