FYI for others looking at this thread, I thought that 2SV might be the problem as well, but Gmail still complains even after Xfinity two-step verification was turned off, so it is evidently hit or miss. Very frustrating, to say the least.

Thank you for reaching out to us on our forums @user_wr1f1b! We appreciate you for checking if two-step verification could be causing this. Could you please reset/change the password for your Xfinity email following the steps in this link here?

After changing the password, please log out/remove the email from your Gmail. Then please make sure your email has third party access enabled. To enable third-party access, please:

1. Sign in to your comcast email through the website here
2. Select the settings (gear icon) in the top right
3. Select “Email Settings” below the gear icon
4. Select “Security” in the top left
5. Make sure the box below “Third Party Access Security” is checked.

After changing the password, deleting/removing the email from Gmail, and enabling third-party access we will want to follow the steps in this article here to make sure the Xfinity email is correctly added back to Gmail.

@user_82c86e​ Rats.  I was hoping this would solve it for me. But I don't have 2FA on at all.  I shut off Gmailify and switched to POP3 to now only get errors that they are blocking Gmail IP addresses.

My gmailify link to comcast worked until today and suddenly stopped.  I followed this procedure and IT DOES NOT WORK.  Gmail continues to show "Username and password don't match" when I try to add my comcast.net email account using gmailify.  I changed passwords on both accounts, removed the comcast email from gmail, logged out of all devices and disabled and enabled xfinity email third party access. 

user_jucohd thank you for using the Community Forums page to reach out. If you are still coming across the issue with accessing your email account, we may need to have you reach out to our Customer Security Assurance team for additional assistance.

I am also having the same issue comcast will not connect to gmailify but will still connect with outlook and windows mail. So I't could be and  gmailify   and a comcast problem. I noticed in the gmail setting will will not let me immediately enable POP 3, says update in progress whatever that means. I've had similar problems before with gmailify not working and had to wait a few days to reactivate it to get it up and running  again.

@user_rk4hfn I can see how it must be frustrating not to have access to your email. Are you able to access your email via their website? Have you attempted to set up the email again? Here: https://www.xfinity.com/support/articles/third-party-email-access is an article to ensure the setup is correct.

@XfinityArmand​ I do not have an issue accessing GMail. The issues is the password error from Comcast when trying to access using GMailify with GMail.

It is not working. I have disabled 2factor on the Comcast side, and still no luck.

When will this issue be fixed?

yes, I can access everything fine. This is a password error coming from Comcast.

I've been struggling with the same issue for at least a couple of months.  At one point a backlog of comcast emails actually did flow into Gmail, but stopped again.  I've also tried resetting my comcast password, and turning off comcast 2 step verification. No luck.  

Me too, get error message "username and password does not match"

Hi there @cntry2go. I am sorry to see that you are having troubles with your emails. Have you recently updated your password for your Comcast Email? 

I have the same issue. I can access my comcast email using the Xfinity website -- no problem. But a few days ago Comcast stopped working with Gmail -- I am getting the same message "Username and password don't match" from within the Gmail app to "add another email account". Note that I had unlinked the account and now trying to re-add. This was working for > 10 years and now is not working. Root cause seems to be Comcast not accepting the correct username and password. I have attempted multiple times and verified the username and password thoroughly. 

When will this issue be resolved ?

Thank you

It seems as if the majority of the issues reported here are related to this issue, so I am not holding my breath that Comcast will acknowledge the issue or provide any resolution. We are on our own. They hold the cards here and they do have the ability to fix this.

Definitely an ongoing problem on Xfinity's side. Same behavior for me. Worked for years, then began noticing sporadic behaviors. Now Gmailify won't validate credentials, even thought I am signed in successfully directly to Xfinity and using mail on the Xfinity site. I have tried removing the account from Gmail and re-adding. "Username and password don't match." Reviewed all the procedures listed above, no help. J

Hello, @user_ltkstq 

Could you please send our team a direct message with your full name and full address? To send a direct message:
1. In the top right corner, you'll see a little chat icon near the bell icon. Click the direct message icon 
2. Click the "New message" (pencil and paper) icon
3. In the 'To' line, type "Xfinity Support" there. A drop-down list appears. Select "Xfinity Support" from that list (an "Xfinity Support" graphic replaces the "To:" line)
4. Type your message in the text area near the bottom of the window
5. Press Enter to send it. An official employee, such as myself or whoever is first available, will respond. Thanks!

Hey there, hORtons, thanks for reaching out through Xfinity Forums regarding your authentication issues. Have you checked to ensure that everything is set up correctly, https://www.xfinity.com/support/articles/third-party-email-access? 

Yes,  it was working fine until mid- November. Then I started getting notifications on my phone the it could not be verified. When I put in my password,  it said username and password did not match. Same as everyone else. . 

Thanks for confirming those details, hORtons. Have you tried restarting your password to see if that helps with the error?

I unlinked my comcast email. Since then I cannot reconnect it as I get the same error that the username and password don't match, even though I have validated that I am using the correct credentials.

If I try to add the account using POP3 it says that the server denied POP3 access for the given username and password.

I have had the same problem for almost two months, and have also tried these and other steps also with poor or no results. other third party email apps like outlook and windows mail seem to work fine with comcast. there are many threads of this problem on this and the google support forum. My conclusion is that there is no desire on comcast or google to fix the problem, so the only reasonable solution is to ditch gmail as an email app.