My email invitations aren't being received
First step - ask the recipients to check their 'Junk' or 'Spam' folder. Sometimes, email providers mark our emails as junk and they don't land in Rater's inboxes.
Second step - if the emails aren't there, you might need to talk to your own IT support. Ask them to whitelist our domain name 20q.co.uk so that emails are allowed through the spam filter.
In some cases, in schools especially, IT Support teams set up policies that stop students receiving emails from non-school domains. Such policies will stop our emails being delivered and will have to be adjusted.