Hello,
Please refer the engine/etc/snapcreator.properties file
You will see an encrypted password -
Please let me know if you use that password whether your GUI lets you in.
Alternatively, you may try to change the password in the SNAPCREATOR_PASS and see if that works.
I tried this in the lab myself, and I am getting the same results as you.
I have reached out to the developers and will keep you posted with an update.
Thanks,
Siva Ramanathan
Snapcreator Community Moderator