External sharing links are working to my gmail account but not coming through to my Outlook account?

I’m testing external sharing in a new hub library. It’s working fine when I share to my personal gmail account – I can share a document, get a link and access the doc.

But I’m not getting the same sharing links when I share the same doc to my Outlook work account. Both are external addresses. I’ve checked my Outlook junk and clutter folders but I can’t find the links. Yet I can see they have been sent (in the sent items) from my admin email account.  

I’ve tried copying the link and pasting it into a new message from my gmail and sending it to my work Outlook and that works.

But when I use the sharing command and put in my Outlook work email address  - I’m simply not getting the emails.

Any ideas why that would be? Thanks, Vicki