Always prompting Permission denied (publickey) after restarting the application or computer

[weehong]

I keep receiving this error message when I tried to commit and push my code after restarting or restart my computer.

git@bitbucket.org: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

I added the key for the first time, until next time I restarted the application, it prompts me again.

May I know how to rectify this issue?

I am using Git Bash and Windows 10.