New prospect errors when joining

I'm having two problems when new people get added as prospects. The prospects have received the email had have opted in and approved their addition:

1. prospects names do not appear in a popup when the first 4 letters are typed, member names to popup
2. more importantly: when a new person joins, the don't receive the email to create a password, instead they get an error shown in the attachment.

If you are using Firefox, try Chrome.

I've tried Chrome, Firefox, and DuckDuckGo browser. Regular modes and incognito modes.

I tested the "forgot password" for members. This works. 

Does anyone have any solution suggestions for this? It's still not working.

The opt-in process for Prospects and Guests is only for them to grant permission to store their contact info in the club site.

1. A Prospect or Guest will not appear in this field when typing their name.
2. The error message you see is normal site response because only people in the Members list can enter the site.

Ok, thank you.