[BUG] Microsoft Partner Center connector issue

Type of Connector

Independent Publisher Connector

Name of Connector

Microsoft Partner Center

Describe the bug

Hi Team, I deployed Microsoft Partner Center custom connector (see PR https://github.com/microsoft/PowerPlatformConnectors/pull/1834 ), but no one can use it.
I have a lot of emails from users complaining this connector doesn't work. I applied all required when create a PR, and then it was tested by MS custom connector team and finally deployed. But it doesn't work - I have success usage rate 0.
And even I can't use this deployed connector. For example, when I use "Get all customers" action it requires creating a connection.
And when I press "Sign-In", I retrieve the following error:

I created ticket to Power Automate team, I created a ticket to Partner Center team, but both teams claim this issue is out of their scope and closed requests and redirected me to open issue on Github.
Please help to fix the issue, or direct me to what changes I have to do to fix it.
Thank you in advance.

Is this a security bug?

No, this is not a security bug

What is the severity of this bug?

Severity 1 - Connector is broken or there's a very serious issue

To Reproduce

Create manually triggered flow and add action "Get All Customers" from Microsoft Partner Center. Try to sign in:

Expected behavior

This action should return all customers from MPC

Environment summary

Install Method - paconn
CLI version (paconn --version). As I developed it more than 1 year ago, I don't remember what paconn I used
Windows 10

Additional context

No additional context

Start by reviewing PR 1834 and reproducing the issue with a manually triggered flow using the Microsoft Partner Center connector and its “Get All Customers” action. Investigate the sign-in failure shown in the issue; done means the connection can be created and the action returns all customers.