Bouning email address

A member of club#3993 Framingham-Natick Toastmaster had an issue with his email address. He entered it again in his profile..now whenever mail is sent out of FTH, there is a message: uf.14@icloud.com was skipped because it has previously bounced too many times.
I sent him an email message using that email address and it didn't bounce. Was it black listed from issues earlier?

the error we are seeing is

Your email message to uf.14@icloud.com could not be delivered
and was returned to the FreeToastHost server. Details are as follows:

Recipient Email Address: uf.14@icloud.com
Email Subject: Please help me prepare for my presentation
Date Sent: Wed, 21 Jul 2021 16:27:35 -0400

Diagnostic Code: 554 5.7.1 [CS01] Message rejected due to local policy. Please visit support.apple.com/en-us/HT204137
Delivery Status: 5.7.1 securityerror
Date Last Attempted: Wed, 21 Jul 2021 20:28:29 GMT

The Bounce Count for Email Address [uf.14@icloud.com] has been reset to zero.

Refer to the following user documentation for other ways that your recipient may be able to use to remedy this problem:
support.toastmastersclubs.org/doc/item/e...embers-receive-email