Someone has already added that key as an access key to a repository.

[bashar]

Hello,

from other answers i'm supposed to see a username here, but I'm not, how to find out which repo having my key added?

ssh -T git@bitbucket.org
authenticated via ssh key.

You can use git to connect to Bitbucket. Shell access is disabled

[Syahrul]

G'Day! @bashar 

Welcome to the community!

I am creating a support ticket for this issue since we need some personal information to continue investigating the location of the SSH key.

Cheers,
Syahrul