Internal server error when sending an email

[#1]

I'm getting an internal server error when trying to send an email using Thunderbird.

It's been fine for months, but I haven't been able to send an email in the past few day,

[#2]

Which email brand?

[#3]

What error code?

On network or off network?

What platform?

What AV software?

[#4]

I've had the same today (4.3.2 Internal Server Error) on force9 whilst on Plusnet network without authentication. I've solved it by switching to authentication. (AV is Kaspersky but eliminated that as a cause).

[#5]

Do you have a static IP address?

[#6]

Yes, I have had a static IP for many many years. (Was a necessity at the time for dialup modem access to my office network, no longer essential)

[#7]

I'm having the same issue.  Every attempt at sending an email returns an "Internal Server Error".  I can receive emails without an issue.

Force9 account, Thunderbird client, and not using a static ip, Windows 10.

[#8]

For me this is: Force9 account, Thunderbird client, fixed IP, Windows 10.

[#9]

Hi @MRChambers @MrZeno @remikz 

Could you please try sending an email via webmail and let me know if you see a more specific error message?

Speak soon, 

Katie

[#10]

Using Firefox I successfully sent an email from the force9 webmail to my gmail account ok, no error.

This suggests a problem with Thunderbird configuration?  If so then this is odd how it has suddenly begun after years of no issues.

Thank you.

[#11 · Accepted solution]

@Katie_B 

Sending via webmail will totally side step the issue here.

The summary of this issue (Server error 4.3.2) gathered elsewhere suggests the following profile:

• SMTP: relay.force9.net
• AUTHENTICATION: None
• Possibly having a static IP address might be a factor

Setting authentication will eliminate the issue ... unless the user's (whatever) is on the black list.

@plusnettony has requested (via the new forum team) that examples of the 4.3.2 server issue be gathered and added to the open incident.

BTW - your 'bravery' of stepping in to the complexity of the email space is welcomed and admired!

[#12]

---

@MrZeno wrote:

This suggests a problem with Thunderbird configuration?  If so then this is odd how it has suddenly begun after years of no issues.

This is not a client configuration issue in its self.  Your reflection suggests that your configuration has never been set up to require authentication ... which up to a point is fine, so long as the device is never on a network which is not PlusNet's.

[#13]

I've done what you said about changing the authentication to none, and it didn't work.  So, I've gone through every authentication and connection security options and either I get a timeout or internal sever error.

[#14]

Since start of october I have had exactly the same Internal server error problem with sending SMTP port 25. Sending works using Thunderbird under Linux on SSL/TLS port 465. I have tried copying the setup from Thunderbird into Pegasus Mail running in Wine under Linux but it won't even start the dialog with the server. I suspect this is because Pegasus is an ancient Win3.1 program and does not support the current protocol, it is missing some of the setup options in Thunderbird. It would be really handy if port 25 worked like it used to because Pegasus is my daily driver for mail.

[#15]

Email brand is vitally important in these discussions.  Internal server error has been encountered on Force9 and free-online but not Plusnet email brands.

It does not matter which SMTP port is used.

It is only encountered where the connection attempt is NOT AUTNETICATED.

In terms of being compliant to recognised standards, neither port 25 or 465 should be used.

The correct settings for the SMTP server are...

• Port: 587
• Authentication: same as incoming server
• Encryption: STARTTLS (or TLS on some non-standard email clients)

The actual server is that applicable to the email brand.

In passing, it is of some interest to know if those users encountering the issue have a static IP address.