Why do I get an error message while linking Stack Overflow?

[noirparliament_]

Hello community people,

Whenever I try to link my Stack Overflow account to my Fiverr account, I just cannot add the account. A window pops up saying - "This window will close automatically." (I have attached the message image) The pop up window then closes itself automatically. After that, the Stack Overflow account is never added to my Fiverr profile.

Please tell me how I can link this to my Fiverr account.

Thanks a lot.