To resolve this issue:
If you're mid deployment you'll need to update the config-journal.json ( & possibly the config-initial.json) file with the correct user name for the PSC/VCSA management user only, by dropping the domain portion (ie. @vsphere.local). Once you update the file restart marvin service and re-try validation. You shouldn't have to RASR the nodes and start the build again.
*This might also happen during node adds.
You may also RASR nodes and retry the deployment and use management username without a domain. (If the above step fails and you still get the same build error)
Example: "management"
Another issue might come up in 4.7.535 is that the password provided in the wizard is accepted, but isn't supported. Use of ! is not allowed. Special char - is allowed, so used that:
Steps to fix this:
1) Generate the new blowfish with the new password:
echo -n "T3st-01" | openssl bf-cbc -iv 62726f6f6b697673 -nosalt -K $(xxd -p < /etc/vmware-marvin/password.key) | xxd -p
2) The return of this command will be needed to edit the /var/lib/vmware-marvin/config-journal.json file. Search for the entry vcManagementAccount and change the blowfish to the above generated.
3) Restart service vmware-marvin and try again.