Cannot Connect to Server - Temporarily Blocked IP Address

@user_c207d6

Translation: "Just to confirm, you cannot access your https://comca.st/3lyeoQo email account?" simply means "Just to confirm, you cannot access your comcast.net email account?". Don't know why the employee didn't just say that.

Kind of. I can access it without issue but when I try to send or receive anything while connected to my home wifi, I cannot use it. As soon as I disconnect from wifi everything works just fine. The same thing is happening to my wife with her Comcast email. She has it in her phone but nothing works while connected to our home wifi and when she disconnects she can send/receive without issues. 

It's NOT an ISP issue as everything else works while connected to my home wifi (other email accounts, the internet, apps, etc). The only issues is with Comcast email.

It also seems to be intermittent when the blacklisted IP address error happens. There are plenty of people posting about this in the community with no 100% answers yet. Don't understand how Comcast doesn't know what's going on.

I am having the same issue.  I recently cannot send email when connected through our home WiFi.  If I use my phone but disconnect it from WiFi and use the 4G connection, the same email is sent without issue.  Using WiFi, I get error messages stating the email clients cannot connect to the Comcast SMTP server.  This is consistent across multiple devices, multiple OSs, multiple clients.  The common thread is our WiFi.  It feels like the Comcast server is blocking our ISP.  I reached out and got help from a CSA rep who verified we could send and receive email from our accounts using Xfinity Connect interface on a browser.  This took well over 30 minutes to walk through on 2 of our email accounts but did not help nor resolve our issue.  I reached out again by chat and was told to re-install the email client on my wife's MAC.  Again, took a lot of time and did not resolve the issue.

How do I understand the cause and get it resolved?

I guess I will try contacting CSA again and ask them to directly investigate our ISP but I would like to know what about our ISP is causing the issue so I can also communicate with them.

Is there a way to bypass the "first-level" CSA contact and get technical help from someone capable of identifying the cause?

My ISP tech support tried to figure it out.  We bypassed our WiFi router and still had the issue - cannot connect to Comcast's SMTP server.  The ISP thought Comcast must have flagged our IP address for some reason.  To confirm, he moved our internet account to a different range of IP addresses.  This did in fact resolve the issue.

Based on this finding, it appears Comcast is indeed blocking our IP address even though two CSA agents said they were not.  I will call them again and escalate.  Wish me luck.

Still hoping for help through this forum!

I have now been on the phone for an hour and 15 minutes, being transferred to the 7th support agent.  I gave up, lost my temper, and hung up.   This is the most incapable support model I have ever imagined.  The support staff cannot access my account because it is no longer active and transfer me to their security support team.  Then they transfer me back to the regular support team that cannot access my account.  Then they transfer me to a technical support person who tells me my account is not in his region.  Every one of the 6 agents I talked with made me verify my account information again.

This is truly unbelievable and the worst experience ever ever ever.

Time to stop doing business with Comcast.

this is a persistent issue that Comcast obviously either doesn/t know how to resolve or doesn't care. Ive had this issue 3 times over 3 months and never a problem with gmail email - ONLY comcast. The reps spend more time apologizing and saying they understand (at nauseum) but fail to fix the problem. I still waiting 48 hrs later for a fix from level 2 who also doesnt get it.

20+ years with Comcast, I am so ready to dump them -its nauseating how poor their customer service is. 

Comcast Xfinity purposely  blacklist email IPs and it takes for ever to get it fixed but never perman.ently. Who has the time to call their customer service center in the philipines or wherever and then wait for a call back.

Doesnt management know how bad it is or do they just dont care.

I finally got my issue resolved, but never got much help from Comcast.  I did spend a lot of frustrating hours asking.

As I understand, they subscribe to "industry blacklists" and will block your IP if it shows up on one.  There are tools online to find out if your IP address is on one of these lists.  This is one of them:

IP Blacklist Check - Email Blacklist Checker (dnschecker.org)

When I ran this, my IP showed up on 2 lists.

Xfinity would not help me at all.

My Internet Service Provider was similarly not highly motivated to help but did educate me a little.  They had my internet account configured as a "dynamic" IP address.  The blacklisting had nothing to do with my account, but the ISP did not want to "own it" and get it resolved.  Instead, they switched me to a "Fixed" IP address and my email issue with Comcast was fixed.  When I run the blacklist checker now, the results are clean with no blacklisting.

Because my ISP charges extra for a fixed IP, we tried going back to the dynamic configuration.  Our email worked fine for about a month, then stopped again.  I did not even try getting help from Comcast and switched back to the fixed IP configuration, accepting the up-charge from my ISP.

Good luck.

I too am having this issue.  I am getting this error on a desktop PC using Chrome gmail retrieval.  This just started recently.  Looks like it started when Comcast assigned a new dynamic IP to me.  I followed above advice and my IP is on a couple blacklist sites.  I do not understand how or why Comcast would assign a blacklisted IP found within those test sites to me unless that has nothing to do with the error messages indicating a temporary blacklisted IP is in effect.  According to my retrieval logs I had one stretch of several hours of this problem.  Other log entries show successful retrieval at times.

In my case the ISP is Comcast so obviously it is one of their own IP's.  Can this be resolved without having to potentially deal with calling the CSA team based upon negative feedback from other posters here?  I am not sure I should not even need to do anything other than report this and look to Comcast to resolve what looks like might be an internal issue.  Now I suppose it is remotely possible that my PC has been compromised somehow without my knowledge and it is doing something unwanted via my IP.  I highly doubt it but nowadays you never know.