Hi @GRVIPER ,
I have made a test on my side and don't have the issue that you mentioned.
I could create a connection to Blogger with no error.
Firstly, making sure you have used the correct account information.
Then try to solve your problem in the following ways:
Create a connection on Blogger directly in New connection.

Check if Blogger account can log in normally, then consider using a different browser to configure a connection to Blogger.
Best Regards,
Zhongys