VCS root failures on multiple projects.

Hi 

we have multiple projects using different VCS roots. Authentication mechanism is through ssh keys. but nothing seems to be working all of  a sudden.

We see errors on log files as well. 

errors: 

INFO [ical executor 6] -      jetbrains.buildServer.VCS - Cannot load current state for VCS root

Failed for the root '"PullRequest" {instance id=6311, parent internal id=243, parent id=Platform_PullRequest, description: "ssh://git@<githublink>/Platform/repo.git#refs/heads/staging"}: List remote refs failed: com.jcraft.jsch.JSchException: Auth fail

Any help greatly appreciated.