Zoho Assist invites not going out

Zoho Assist invites not going out

I'm new to Zoho Assist so perhaps I'm missing something.   I'm thinking of switching over from Teamviewer, but so far have found the invite by email functionality of Zoho to be non-functional.   Invites simply don't reach the customer.   They can use the link I send and I assume they can also join using join.zoho.com by entering the session ID I give them.    For me, the invitation feature is important in representing a trusted email from me to my clients.   Can you let me know why this is not working.   I should explain I am also on a trial basis at the moment, but if email invites won't go out I will probably not purchase a plan.