Thanks for writing in!
I can see the license was in your a/c in unlock mode, which means it can be transferred to different a/c.
Now, I have locked it.
Also, I can confirm the issue on my end too.
I would suggest you few troubleshooting processes to see if the issue resolved.
1. Please delete the complete theme file and re-upload it via FTP.
2. If you are using child theme please switch to the main theme and perform the validation action.
3. Disable all third-party plugins including jetpack to check if there is a plugin conflict.
4. Check this for validation troubleshooting
If you could please try the above and if you still have the issue we'd be more than happy to assist.