I have sent an invitation to a new user, they have not previously signed up to Zoho - I know this because I created them a fresh company email address myself. 

Upon clicking the invitation link, they reach the page to 'Create a Zoho Account'. They entered their full name and a password but when they click 'Create Account' they receive the following error: 

We are unable to create your account right now. Please contact support-as@zohocorp.com for support. 

I used anydesk to remote-login to their machine and try for them. I was able to sign up as a free trial account and that worked fine. I then delete the free trial account, resend my organisation invitation and again it failed with this error. 

Can anyone assist with this?