Azure server backup – Stuck on Generating backup metadata information

I'm new to Azure and am trying to backup a servers folder (approx. 1.5TB) to Azure recovery vault.

I have correctly connected the server (agent) and our Azure account and the transfer initiates, but has now been stuck on 'Generating backup metadata information and preparing the metadata VHD…' for 18 hours and hasn't yet transferred any data.

While 1.5TB is a lot of data, it hasn't even yet started to transfer anything.

My initial question is, is 18 hours too long and should I cancel it down and look elsewhere? Our internet line is a dedicated 200MB line, so I would have thought that, while the data is expected to take a while to transfer, at least it should have started sooner than this?

The folder I am trying to backup is a specific folder on a Windows Server 2012 holding 1.23TB in 631,000 files.

I don't really want to stop the job if it IS actually doing something.

Any advice/pointers would be greatly appreciated.

Thank you.

EDIT : CloudBackup event viewer log says :

Successfully updated the backup schedule for Azure Backup.

The backup operation has started.

The backup operation has started.

Storage quota is within limits.

Storage quota is within limits.

Storage quota is within limits.