BitBucket 6.4 LFS File Locking Issue

[Dalectric]

I've upgraded my Bitbucket test server (running Windows) to 6.4 and Git 2.22.0.

I wanted to try out the LFS file locking and it's enabled in Bitbucket for the server and the repo I'm using.

However when I try and push a file I've marked as wanting to store in LFS (In Sourcetree) it comes back with the following

Remote "origin" does not support the LFS locking API.

 How can I fix this?