Outlook for Mac has been unable to sync with my Charter server to upload incoming e-mails.

Question

Outlook for Mac has been unable to sync with my Charter server to upload incoming e-mails.

Marcye Britt 25

Since trying to forward a message with several photo attachments which would not send, Outlook for Mac hung up and I had to shut down my laptop (a newish MacPro). Now Outlook for Mac is no longer able to sync with my e-mail provider's server (Spectrum). There is no Outbox folder so nothing is waiting in a queue. There is nothing in Sent mail so the mail didn't send; recipients have confirmed they did not receive the message. Spectrum agent says they do not support apps outside of their own webmail app (which I can access and have been using for testing). I tried deleting the Charter (POP) account in Outlook, then recreating it - that didn't work. I tried changing the SSL port settings as recommended by Gemini, that produced a different error message. The attached file shows the account settings that have always worked until yesterday morning. The error code is: 3253 Connection to server failed or was dropped. It is the same message for sending and receiving. I have been using Legacy Outlook for Mac because I don't want to lose access to my saved messages and folder structure. I would like to continue using it for obvious reasons. What else can I do to get this working again?

Marcye Britt 25 Reputation points

2026-08-22T20:02:39.16+00:00

AI bot replied:

For a POP account in Outlook for Mac, the supported next checks are: Verify Outlook is online. In Outlook, open the Outlook menu. Make sure Work Offline is not checked. Confirm the Mac still has network access. Open a web browser and verify websites load. Since webmail works, the general internet connection is available, but Outlook can still fail if the outgoing or incoming mail path is blocked. [---]

The answer has not solved the issue although I will try contacting the ISP again to find out if Outlook can be directed to another server. The answer I got first time is that Spectrum does not support mail apps except their own webmail.

Answer accepted by question author

EmilyS726 264.1K Independent Advisor

There are signs of a Spectrum/Charter email problem today, August 22, particularly involving third-party email clients.

A user posted in Spectrum’s official subreddit just a few hours ago saying their charter.net email suddenly stopped working in Thunderbird yesterday, while Spectrum webmail continues to work. That is extremely similar to this Outlook for Mac case. A Spectrum representative replied that they are not currently seeing a formally recognized outage, so Spectrum has not officially confirmed a widespread incident yet. https://www.reddit.com/r/Spectrum_Official/comments/1vvj2p1/is_there_any_known_issue_with_charternet_servers/

More importantly, independent email-delivery telemetry is currently flagging Spectrum / Charter as having issues. As of late August 21, its retry rate was an unusually high 34.6%, compared with essentially zero for several other major providers. About 99.5% of the Spectrum failures were "Temporary resource unavailable." https://prr.groups.io/email-provider-status?isp=Spectrum+%2F+Charter

So I would not assume Outlook or the Mac is damaged yet. Perhaps talk to Spectrum first, use the web mail for now and wait for the issue to resolve, likely on its own from Spectrum's side.

Marcye Britt 25 Reputation points

2026-08-22T21:19:41.81+00:00

I decided to config Apple Mail to see if the problem exists in that app -- and it's the same issue.

2 additional answers

Your answer

Marcye Britt 25 Reputation points

2026-08-22T20:02:39.16+00:00

AI bot replied:

For a POP account in Outlook for Mac, the supported next checks are: Verify Outlook is online. In Outlook, open the Outlook menu. Make sure Work Offline is not checked. Confirm the Mac still has network access. Open a web browser and verify websites load. Since webmail works, the general internet connection is available, but Outlook can still fail if the outgoing or incoming mail path is blocked. [---]

The answer has not solved the issue although I will try contacting the ISP again to find out if Outlook can be directed to another server. The answer I got first time is that Spectrum does not support mail apps except their own webmail.
Marcye Britt 25 Reputation points

2026-08-22T21:19:41.81+00:00

I decided to config Apple Mail to see if the problem exists in that app -- and it's the same issue.

Answer 1

KBeard 0

i've had this same issue. i contacted Spectrum tech support, insisted on a human agent and when i got into the wait queue on the phone, i got a voice message that Charter, (spectrum), was experiencing issues with outlook on desktops and that their engineers were working on the issue with microsoft. about 24 hours later it was working again. now today, 8/29 its broken again. I have tried all the suggested fixes including deleting the account and adding it back in. nothing works. interestingly, outlook app on my iphone works, but not on my tablet. deeply annoying.

SB06 0 Reputation points

2026-08-30T22:34:32.62+00:00

I had the the same experience as KBeard today, except that Outlook for Android is also broken. The CSR at Spectrum kept putting me on hold to talk with his "team leader". After 45 minutes they were not even acknowledging the Spectrum recorded message that I heard on 8/22 confirming a problem with Outlook. The issue seemed to resolve on 8/25, and then charter.net email failed again on 8/28 in the afternoon (EST).

Gmail running on MS Outlook classic (2021 on Win 10, 2024 on Win 11) seems to be working. One of my charter accounts also passed through to Gmail app on phone the first time the problem occurred, but not this time.

Despite Spectrum's failure (at least according to my call today) to address the issue further, it does not seem to me likely that they caused this problem. It would be nice if Microsoft could acknowledge the issue and indicate that they're working on a solution.

Answer 2

For a POP account in Outlook for Mac, the supported next checks are:

Verify Outlook is online.
- In Outlook, open the Outlook menu.
- Make sure Work Offline is not checked.
Confirm the Mac still has network access.
- Open a web browser and verify websites load.
- Since webmail works, the general internet connection is available, but Outlook can still fail if the outgoing or incoming mail path is blocked.
Recheck the POP account credentials and server settings.
- Go to Tools > Accounts.
- Select the Charter/Spectrum POP account.
- Verify the email address, user name, and password.
- If Spectrum requires special settings, confirm SSL and port values with the provider before changing them again.
Turn on SMTP authentication if it is not already enabled.
- In Tools > Accounts, select the account.
- Under Outgoing server, select More Options.
- Choose the required authentication type and enter the credentials.
- This is relevant because Outlook for Mac notes that some POP and IMAP accounts cannot send unless SMTP authentication is enabled.
Check whether the network or ISP is blocking the SMTP connection.
- Outlook for Mac documents that a firewall on the ISP or network can block connections to the outgoing mail server.
- If that is happening, an alternative SMTP server from the ISP or network administrator is required.
- In the account settings, the replacement is entered in the Outgoing server box.
If the issue started with a message that had several photo attachments, check Drafts for a message that is too large to send.
- Outlook for Mac keeps oversized messages in Drafts, not Outbox.
- Open Drafts and look for the failed forwarded message.
- Remove some attachments and try sending again, or delete the draft.
- If deleting it, also delete it from Trash to fully remove the stuck oversized message.
If the mail server is unavailable, Outlook cannot send or receive.
- Since Spectrum webmail works, the mailbox itself is likely available, but Outlook for Mac guidance still recommends confirming server availability with the provider when the client cannot connect.

Because the account was already removed and re-added, the most relevant remaining self-service steps are:

verify Work Offline is off,
verify credentials and POP/SMTP settings,
enable SMTP authentication,
remove any oversized draft message,
and check whether the ISP/network is blocking the configured SMTP server.

Error 3253 is listed by Microsoft as one of the send/receive errors covered by Outlook troubleshooting, but the Mac-specific guidance in the available documentation points to connection, authentication, server settings, server availability, or SMTP blocking as the main causes.

If the oversized message cleanup does not help, use Outlook for Mac’s guided support tool or Help > Contact Support.

References: