What does "Please do not provide email addresses that block or restrict CDC-INFO from responding, thank you." mean?

Some folks have turned on high-security email filtering on their incoming POP3 email server. Usually that means they won’t get an email unless it’s from an address on an approved list.
If CDC-INFO were not on that list for someone with that security/spam-filter mode then CDC-INFO would not be able to respond.

It is possible to have white list and black list emails. If you are not sure, keep checking your spam folder for the CDC mail then click “Not Spam”. That will tell your filter to add it to the white list.
Sadly spammers have been such an annoyance that we now throw out good stuff by mistake. This is happening with our phones too. We don’t answer because it is often telemarketers and scammers. We miss the call from our long lost cousin in Arizona.

How interesting. I thought they were referring to my email address. I thought “What kind of email address should I never have to make sure that CDC INFO would always respond to me?Is something like flo@gmail okay?”
I wish they had ”... your filter….”

Thank you both.