Logging in to my.kepware.com fails after modification of email address in PTC account

Our company was renamed. Therefore, it was also necessary to change the email address associated with my PTC user account.
Previously, I was able to authenticate with my PTC user account credentials at https://my.kepware.com as well.
However, the login fails since the change of the email address. I can successfully log in with my PTC account at https://support.ptc.com. However, I can no longer log in to https://my.kepware.com with the identical credentials.

Resetting the password of my PTC account did not help.

To the PTC staff here: What do I need to do?