No errors there. I’ve added a link to the server configuration below which may help.
My hosting support are saying they don’t block requests like this so it’s not them, but I’m seeing the error on all my sites I host on that server. It definitely worked before and they do say no changes have been made. It works fine on sites I have elsewhere. I’m sure the error is with the server, but would be good to narrow down the issue so I can go to them with specifics.