Seeing this error:
"Sign In Failed. This Adobe ID has already been used to activate the software on two other computers or devices." No, it hasn't been.
Please contact Adobe Customer Support.They should be able to clear this up for you. Start by logging in to adobe.com with your Adobe ID and then contact Support at the link below. Click on Still Need Help button and choose the Chat option : support
Please refer to the help document below:
You may refer to the thread below where this issue has been addressed:
It seems the Adobe CC is already activated on two machines with your Adobe ID.