SMTP Error: Mailbox name not allowed. The server response was: 5.7.1 - Sender address rejected: not logged in

Support
1

Hi there, I hope someone can give some advice on this.

I’m trying to configure SMTP settings with one of my emails, but I’m getting the following error:

Mailbox name not allowed. The server response was: 5.7.1 <my@email.com>: Sender address rejected: not logged in

I’m trying to use an SMTP token as my email provider, ProtonMail, doesn’t allow generic IMAP/SMTP settings. I’ve emailed ProtonMail and their response was as follows:

This error means your accounting software did not follow the SMTP (protocol) to send email . It skipped the username and password steps .
A common reason could be that the accounting software didn’t run the AUTH PLAIN and Credentials commands "after " the STARTTLS command or skipped them for unknown reasons.
Note: This is a system bug on the accounting software. Only their IT team can fix it.

< Technical Details for their IT Team >

A normal connection should look like this:

TELNET smtp.protonmail.ch 587
EHLO mail.*****.com
STARTTLS
AUTH PLAIN
Credentials (Username and Password encoded by Based64)
MAIL FROM: <***>
RCPT TO: <***>
...
..

You can double-check why the accounting software skipped AUTH PLAIN and Credentials steps after STARTTLS.

Here’s a screenshot of my SMTP settings screen in QuickFile (with fake details for privacy):

image
image712×475 21.6 KB

Any advice on this would be much appreciated! My email supplier is also happy to take any questions on the matter, if it’s something I’m not able to answer.

Thank you, and all the best,
Alex

2

Is the username definitely supposed to be the email address? It varies by provider as to whether the username is the same as your email or is some other name that you would use to log in to their web control panel or similar.

3

Good idea, but I’ve just double-checked - definitely the email address as the username. Thanks for the suggestion though!

4

I still haven’t managed to get this working - are there any support staff who are able to speak to me about this, please?

5

Hello @alasdair

When setting up smtp settings, did you recieve an activation code?
Did you enter it here?

image

I also found this on the Proton mail website if it helps

6

Hi Steve,

Thanks for your message. No, I never received a code by email - I did make sure to check just in case.

7

Hi @alasdair

I’m not personally familiar with Protonmail, but we’re not doing anything special with the SMTP connection - it’s a standard connection.

However, I’ve just done a quick search and have some suggestions which may help:

  • Try changing the SMTP server to mail.protonmail.ch rather than smtp.protonmail.ch

  • I’ve seen some suggestions that suggest port 1025 instead of 587

Do you use these SMTP settings elsewhere (e.g. on your phone, in an email client, etc.)? If so, are the exactly as you see them there?

8

Hi Mathew,

Thanks for your response. I’ve tried those settings but it just times me out.

I’ll get back to Protonmail and ask if they have any other suggestions.

Thanks,
Alex

9

Hi @QFMathew,

I’ve received this response from Protonmail:

According to the error message, your settings are correct. The problem is that:

  • QuickFile “should” first send the AUTH PLAIN command and your credential (username+password encoded by based64) after establishing a TLS connection. Then, sends the MAIL FROM, RCPT TO, and other commands.
    - However, QuickFile sent MAIL FROM first after establishing the TLS connection. This is an ordering issue.

QuickFile’s software engineers should check their programming codes and verify this. QuickFile’s engineers can also contact our engineers at postmaster@proton.me. We can help them clarify details.

I’m not sure if this is something you can look into or not, but thought it was worth sharing with you in any case.

Thanks and all the best,
Alex

10

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