Invalid SSH key

[siggib007]

Trying to set up a new SSH key between sourcetree and Bitbucket. We have an internal bitbucket at work and I store my personal stuff in the public bitbucket. I changed my SSH key at work and I'm trying to set up the same Key in my personal buckets. However when I do I get "Invalid SSH key". I'm following the instructions on https://confluence.atlassian.com/bitbucket/set-up-an-ssh-key-728138079.html#SetupanSSHkey-ssh3. 

[siggib007]

Looks like I had already uploaded the key before, so then why am I getting

git -c diff.mnemonicprefix=false -c core.quotepath=false push -v --tags origin master:master
Pushing to git@bitbucket.org:siggib007/python.git
FATAL ERROR: Server unexpectedly closed network connection
fatal: Could not read from remote repository.

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