apple photos is not sharing albums with gmail address

I have created a shared album in Photos. I want to share it with my gmail address. The request does not appear to go through to the gmail address. I have tried various gmail addresses. I do have the "public website" box checked for the sharing..... My gmail addresses are not getting any invitations to accept. I sent an invite to my husband at his office address and it came through on his iPhone just fine - but it was not a gmail address. Does the recipient have to have an Apple product to be able to get the invite....i wouldn't think so....