I cannot send emails through Outlook.

Question

I cannot send emails through Outlook.

Charles White 0

I have been sent to Outlook by local internet provider, Hartcom, because I cannot send emails through Outlook. The error message is displayed differently on my home desktop and my phone. The sent messages are going to my Outbox on my phone and the error message says, "Cannot send mail. Connection with the outgoing Hartcom server failed."

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2 answers

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Answer 1

Welcome Charles White,

Thanks for reaching out to Microsoft Q&A Forum. I understand that you can't send emails with your Hartcom account in classic Outlook for Windows or on your phone. On your phone, messages stay in the Outbox with the error "Cannot send mail. Connection with the outgoing Hartcom server failed."

To narrow down the issue, could you share:

Did this start after a recent change, such as a password reset, a new router or modem, or a notice from Hartcom about changes to its email service?
What exact error message appears in classic Outlook on your desktop, and does the problem still happen on your phone when you switch from Wi-Fi to mobile data?

Please make sure you already tried the Q&A Assist steps. In addition, please try the following:

1, Check the date, time and time zone on both devices

On Windows, go to Settings > Time & language > Date & time, turn on Set time automatically, then select Sync now.
On the phone, turn on automatic date and time in the phone's settings.
If the clock is wrong, the secure connection to the outgoing server can fail.

2, Turn off anything that might filter the connection, then test

On the desktop, turn off email scanning or the mail shield in your antivirus or security software for a short time, then send a test email.
On both devices, disconnect any VPN. On iPhone, also turn off iCloud Private Relay or Limit IP Address Tracking for your Wi-Fi network, then try again.
Turn these protections back on after testing.

3, Update the saved Hartcom password on Windows

Close Outlook.
Open Control Panel > User Accounts > Credential Manager > Windows Credentials.
Remove the saved entries for your Hartcom email address or Hartcom mail server.
Open Outlook again and enter your current Hartcom password when asked. Select Remember my password.

4, Start classic Outlook in safe mode to rule out add-ins

Press Windows key + R, type outlook.exe /safe, then press Enter.
Send a short test email.
If it sends, go to File > Options > Add-ins, select COM Add-ins, choose Go, clear the add-in checkboxes, then restart Outlook normally.

Looking forward to your update.

Emma1-N 14,925 Reputation points Microsoft External Staff Moderator

2026-11-11T07:19:10.9933333+00:00

Hello Charles White,

I just wanted to check if my previous response addressed your question correctly. If there is anything I may have misunderstood, I would truly appreciate it if you could provide a bit more detail to help me better understand your needs.

Answer 2

Obtain Hartcom’s current SMTP settings and enter them separately on both devices; the same outgoing-server failure across desktop and phone points to the Hartcom mail service or its SMTP configuration rather than a single Outlook installation.

1. Ask Hartcom for the complete outgoing-mail settings

Request these specific values:

SMTP host name
SMTP port
Encryption type: SSL/TLS, STARTTLS, or none
Whether SMTP authentication is required
SMTP username—often the complete email address
Whether the normal password or an app-specific password is required
Whether outgoing mail is restricted to Hartcom’s own internet connection
Whether its outgoing server is currently operational

Do not substitute Outlook.com or Microsoft 365 server values: Hartcom hosts this mailbox, so Hartcom must provide the applicable server details. Microsoft identifies the SMTP host name, username, password, and SSL requirement as provider-supplied outgoing-mail settings.^1^

2. Update classic Outlook on the desktop

Close Outlook.
In the Windows search box, enter Control Panel and open it.
Search for and open Mail (Microsoft Outlook).
Select Email Accounts.
Select the Hartcom account, then Change.
Replace the Outgoing mail server (SMTP) value with the exact server name supplied by Hartcom.
Verify the username and password.
Select More Settings:
- Under Outgoing Server, apply Hartcom’s authentication requirement. If Hartcom says to use the same credentials as incoming mail, select that option.
- Under Advanced, enter Hartcom’s SMTP port and encryption type exactly.
Select OK and then Test Account Settings.

Two green check marks indicate that Outlook can connect successfully. Red markers mean the configuration or Hartcom connection is still failing; Microsoft directs users to verify those values with the email provider.^2^

Alternatively, inside classic Outlook, use File > Account Settings > Account Settings > Server Settings > Outgoing mail, enter the corrected values, and select Next > Done.^2^

3. Correct the phone’s outgoing-server entry

The exact menu depends on whether the phone uses the Outlook app, Apple Mail, or Android’s mail application. Open the Hartcom account’s advanced or server settings and update these fields:

SMTP host name
SMTP username
SMTP password
Port
SSL/TLS setting
Authentication, if shown

Use the Hartcom-provided values exactly. Automatic SMTP discovery does not always succeed for smaller providers; Microsoft’s documented action in that case is to obtain the SMTP details from the provider and enter them through advanced setup.^3^

After saving, send a new short message without an attachment. Existing messages in the Outbox may need to be opened and sent again.

4. Separate a Hartcom server problem from a device problem

Try sending a short message from Hartcom’s webmail site, if one is available:

Webmail also cannot send: Hartcom needs to check the mailbox status, SMTP service, password/account lock, and any outage.
Webmail sends, but both devices fail: give Hartcom the SMTP host, port, encryption, and authentication settings currently shown on each device. Ask them to identify which field differs from their required configuration.
Desktop starts working but the phone does not: the remaining issue is the phone account configuration; update or remove and re-add only that phone account using Hartcom’s manual settings.

If classic Outlook displays Disconnected, Working Offline, or Trying to connect, select Send/Receive > Work Offline to return online and resend. If only one particular message remains stuck, remove any large attachment and retry.^4^

Do not remove or recreate the desktop Outlook profile until the SMTP test has been performed with confirmed Hartcom values. A new profile configured with the same incorrect or unavailable server will fail in the same way.

References