Cannot connect to postgres SQL to power BI desktop occurring the error

Hi Khushidesai0109 

Thanks for the reply from Tahreem24 and Ritaf1983 .

If your problem still hasn't been resolved, you might consider trying the following. Here's a post I found with a similar error to yours. The solution in it is: Go to File –> Options and Settings –> Data Source Settings, under Global Permissions, select clear old data source connection permissions, and then click Edit Permissions in Power BI Desktop. Then try to connect again and check if it succeeds.

Solved: We couldn’t authenticate with your credentials. Pl... - Microsoft Fabric Community

Hope this helps!

Best Regards,
Yulia Xu