Failed in sending the link of mail invites while creating new user with viewer role.

Hello,

I have implemented PMM through docker in AWS EC2 instance.
I have been monitoring AWS RDS instance.
We want to create new user with viewer role but while sending invitation link, its giving error.
Also on same EC2 instance, we have implemented SMTP server and we have successfully tested mails.

Does anyone knows how to add new user with viewer role in PMM tool?