Problem with Transferwise transfer

We are trying to transfer $$ in my mil account at Lloyds so we can pay a deposit on a house we just rented.  The transfer went through on our end but Lloyds refused the money.  We believe it flagged by the fraud squad.  They want the "field senders reference number".  Has anyone had this issue?  I called Transferwise and support didn't seem to know what that was.  Help!

When I switched to TransferWise I had some issues with it coming from a small regional credit union in the US. It came the first time somehow but then wouldn't work. Over a period of a week or so several people tried to help me, but there was just an issue with the smaller banks that they said they were going to straighten out in the near future. I was dealing with the same person for a bunch of this and finally they got someone to deal with my problem and put in some kind of special OK on my account that allowed things to work. The issue of money laundering affects quite a few bank issues. When we bought our house here in the UK 2 years ago we had to jump through some hoops to prove that the money was ours and not a money laundering issue.

Not had a problem like this but F4's explanation above sounds about right.