E-mails sent to Comcast are being Throttled

Hi, 

I work for a company that has a few hundred employees. Those employees use their own personal e-mail addresses to receive e-mail from us. Some of those employees use @comcast.net e-mail address as their personal e-mail account to receive those messages from us. When we send to all of our employees from our domain using a distribution list all of the e-mails get sent perfectly fine except the ones going to the @comcast.net employees. We get a bounce back message when we send to the Comcast employees, here is that error: 

Reason: [{LED=451 4.2.0 Throttled - https://postmaster.comcast.net/#RL000010};{MSG=};{FQDN=mx1.mxge.comcast.net};{IP=2001:558:fd00:4f::4};{LRT=1/24/2024 2:01:32 PM}]. OutboundProxyTargetIP: 2001:558:fd00:4f::4. OutboundProxyTargetHostName: mx1.mxge.comcast.net

This has been happening for months now. Our mail server is Microsoft Exchange and I've already spoken to them, this is on Comcast's end of things not theirs. I've also tried to use your form where you put in your IP address and I just get an automated response saying that our IP is not blocked. This issue is not that it's being blocked it's that it's being throttled. 

I've tried to call the CSA team at Comcast(1-888-565-4329) and they are no help whatsoever. I just keep getting passed around and asked the same questions, they do not understand the issue. A level 1 person answering the phone over there isn't going to be able to help with this, I need whoever administers Comcast's servers to help with this. We cannot send e-mail to our employees and it is causing a huge issue. I've seen this issue posted on here by several other people as well, so this is a known issue with Comcast, there has to be a way to fix this for us! 

Can you please help me!!!