Nationwide Account access restricted due to UN Sanctions?

I’ve (a very normal/average 25F) just logged into my Nationwide account on both my phone & laptop to see that my accounts have disappeared.

After speaking to an Agent online, he’s told me that my account has access restrictions due to UN sanctions..

I’m heading into the branch today, but I have no idea what’s going on or what I’m in store for. If you have any advice even if it seems obvious to you please let me know.