I cannot login to panorama in azure after downgrade from version 10.0 to 9.1.5.

[kakuda.tomoyuki]

Hello

I deployed the panorama(version10.0) in my azure environment.
After setting up, I realized that I must downgrade to version 9.1.5 due to several reasons.
Therefore I tried downgrade with this manual site( https://docs.paloaltonetworks.com/panorama/10-0/panorama-admin/troubleshooting/downgrade-from-panora... )

It seems panorama is downgraded, however I can not login it at the moment.

I do not know why but the ID and password are changed.
Of course I tried default ID and password( ID: admin, Password: admin) but it not available as well.

How can I solve this issue?

please help

[kakuda.tomoyuki]

[Additional info]

I found, unfortunately I miss-selected "autosave-pre-cfg-202001XX.xml" for configuration while downgrading.
In this case anyone know how to recover?
According to my investigation, it is impossible to recover. I'm about to give up( it means I will re-install)