email blocked to and from Charter when on Comcast

I suspect the first issue might be related to the Windows Firewall. It sounds like it can't contact the remote system.

When you're trying to send email and get an error, what is the specific text of the error?  We have colleagues at Charter that may be able to help.

Thank you for answering. I am answering as a comment rather than a reply because I read a message that Xfinity sees comments and not replies.

The error message I get says 

"impout001.msg,chrl.nc.chartr.net champ <my internet-facing IP address> blocked. Please see https://www.spectrum.net/support/understanding-email-error-codes for more information. AUP#Out-1130"

"Mail could not be sent"

"Error code: -17099"

I thought it would be wrong to list my exact IP address? Should I? What I mean by internet-facing is the  Comcast-provided IP address that I see listed when I log onto my router, not the 192.168 .... addresses of my local computers.

I get several of these messages for one attempt. The "X" in "impout00X.msg ... varies like impout007, impout006, etc.

When I look up the information with the provided URL,  I see for 1100-1150 (I had 1130)

"The IP address you're trying to connect from has an issue with the Domain Name System. Spectrum equips a full circle DNS for emails to be allowed through. Verify the IP you're connecting from, and check the IP address to ensure a reverse DNS entry exists for the IP. If the IP address is a Spectrum-provided email address, contact us."

I am assuming (?) that the IP address the message refers to is the internet-facing address that Comcast provided me. The sentence that says "If the IP address is a Spectrum-provided email address" confuses me. I don't think of an email address as an IP address, although it might be the IP address of the Charter mail server.

I do not see this issue at my Charter location. I can successfully add my Charter email address to my Outlook client at my Charter location, and it works. However, my Windows machine at that location is running Windows 10 and not Windows 11. My Windows machine at my Comcast location is running Windows 11.

I have screenshots that show in detail what occurs, but I do not know how get them to you.

I am impressed by the timeliness of your reply. I posted my issue just last night.

@tkubaska Can you tell me what your internet-facing IP is?  (feel free to DM it to me if you don't want to publish it here)

All of our (residential) customer IPs should have a valid PTR record for IPv4.  Charter requires a valid PTR record to use their services.  It's possible yours does not, but it's relatively easy for us to fix if that's the case.

I did Direct Message you my IP address. I don't know if it is a security issue to list it here. It's DHCP and will change anyway, but I am jaded enough to be paranoic about the Internet. This is a residential IP address, not a business.

I have chatted with Comcast and Charter Customer Service. Charter assured me yesterday that my Outlook configuration for Charter addresses was correct. Comcast assured me a few days ago that my Outlook configuration for Comcast addresses was correct.

Charter pointed out that Charter webmail was working so that there was nothing wrong with the email address they provided. Charter suggested that I might need a static IP. I don't think that I need a static IP to resolve my issue, but I am not certain. I would need a business account to get a static IP. I am not a business, but if that is what is needed, I will do it.

On my MAC I issued a "dig -x <my IP address>". The output indicated to me that the Comcast-provided IP address is missing a PTR record. I followed the instructions on

https://serverfault.com/questions/148401/how-do-i-check-a-ptr-record

That site gives an example of how dig output looks if my IP address does not have a PTR record and my output looks like that.

Once again, thank you for your attention. I have personally spent nearly three solid days on this issue with no resolution. What concerns me is that my Windows Outlook at my Charter location works with both my Comcast and Charter addresses while my Windows Outlook at my Comcast location only works with my Comcast addresses.

I had been using different machines at those locations (win10 at the Charter location and win11 at the Comcast location). I will carry the win11 laptop here at my Comcast location to my Charter location and test it there. My speculation is that my issue will be resolved at my Charter location. I cannot be positive of course, but I believe at this point that my issue is with my Comcast connection and not with any configuration on my part.

I will report later today or possibly tomorrow what happens at my Charter location.

I am now at my Charter site using the very same laptop I used at my Comcast site. Win11.

My charter email address adds successfully to Outlook, and I can send and receive from it.

This tells me that my issue is not due to Outlook or Microsoft.

I checked my router configuration at both places very carefully and the configuration seems fine.

This used to work at my Comcast location. However, this was with an older computer and older SW (2020).

I did upgrade my modem at my Comcast location within the last few months.  I used an Xfinity app to connect and configure the modem and did not do anything by hand. You guys have been doing this a long time and it is unlikely that the Xfinity app missed anything, but it may be worthwhile checking.  

My Comcast IP address is DHCP and the lease expires this evening (Pacific time). So the IP address I gave in a direct message will change. 

The new modem was a Nighthawk, and the best one I could find. I can look up its specs if you want them.

Thanks for posting the ticket and your careful attention.

Thank you for the information. Currently I am using a different ISP (Charter), but I will check out my Comcast email facility later this month. I am successfully sending and receiving Comcast email with my Charter connection. 

If the ticket that was filed fixes the problem I experienced when using my Comcast connection (I have every confidence that it will), I will mark this thread as an accepted answer.

@tkubaska I spot checked a few in the same network, and they seem to have PTR records.  From what Charter tells me, that should be sufficient.

Does this mean that my email issue is fixed? It'll be a few days before I can check at my Comcast location. Everything is working fine at my Charter location. I can send and receive email in Outlook for both my Comcast and Charter email addresses.

Again, thanks for looking into this. I should mention that I use the same Dell laptop with win11 at both locations. This leads me to believe (can't be 100% sure of course) that the issue is not due to a misconfiguration on my part.

@tkubaska I believe it should be resolved on our side (the missing PTR).  Please follow up when you return to your Comcast location. 

I went to my Comcast location yesterday and all my email accounts work as they should. I marked the solution as accepted.

So now officially XfinityAlex is on my list of heroes.