Hi Karsten - many thanks for your reply.
I’ve done everything you suggested, and I’m still getting this error message.

I also can’t update all my contacts in bulk. As you can see below, the “Finish” button is greyed out, and I can’t do anything.
I’m at my wits’ end here. I just don’t know why this is happening.
Any help gratefully received!
Thanks,
Steve Tilling
