Once email ID is not receiving emails

I am also web administer for Mumbai Toastmasters (Club number 00993448)
Whenever we send email from mtm.toastmastersclubs.org/ website, for one of the email IDs: mtm.toastmastersclubs.org/ , for one of the email IDs I am getting this reply:
vinod.toastmaster@gmail.com was skipped because it has previously bounced too many times.

I have replaced this email ID with another email ID of Vinod Yadav, and he is getting emails on that email ID.

I request you to unblock vinod.toastmaster@gmail.com from the blocked email ID list and confirm.

There is no such email address vinod.toastmaster@gmail.com in club 993448

It is there now: vinod.yadav@gmail.com

I had to change it because this ID was not receiving emails.Please unblock this email ID so that he can receive the emails from the website.

The Bounce Count for Email Address [vinod.toastmaster@gmail.com] has been reset to zero.