Failed to update data source credentials

I am connecting a Power BI report to a MySQL database. It works well with PowerBI (desktop) data refresh manually.

Then, I tried to use MS Power Automate to schedule regular data refresh automatically. The refresh tests seemed successful.

But the attempts actually failed as shown in the Power BI (web) data refresh history. The error was "at least one data source is missing credentials".

However, when I entered the credentials, errors were prompted as follows. How can I solve this issue? Many thanks.