Intermittent issues with downloading resources from BitBucket repository

[donald_macleod]

I have been having intermittent issues with connecting to our BitBucket repository the last week or so. I have recently changed the SSH key and since then I have had multiple days working fine without any problems but then on occasion I get issues where either I have to register the SSH key back again or as with today's issue I get issues like below when I try to do a git pull:

git -c diff.mnemonicprefix=false -c core.quotepath=false fetch --no-tags origin
FATAL ERROR: Network error: Connection refused
fatal: Could not read from remote repository.

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

Completed with errors, see above.

I recently updated to version 3.4.8 of SourceTree, has anyone else had similar issues with this particular version?