Thunderbird error 80004005

Hello,
In fact, I had the same issue (unable to send my ***@*** either via Thunderbird or my Android, all of a sudden, without any changes to the account or settings; receiving has always been fine)
I checked my settings on the laposte.net messaging site (tab "Preferences", then "Accounts" in the left column), and I noticed that my ***@*** address, the one I use daily, is an alias of ***@*** = main account that I do not use... I did this when I created my email address, several years ago, and I had forgotten.
The solution:
1- I changed, in server settings on Android:
Email address: ***@*** (the email I use)
Username: ***@*** (my main account)
Same in "Authentication required to send emails": ***@*** followed by my usual password
2- I changed in Thunderbird in "View settings for this account"/"Modify SMTP server": Username: ***@*** (my main account); I did not change anything else

I should clarify that previously, the email I use (***@***) appeared for both email address AND username, I never indicated the other... and it always worked.

I hope this can help you.

Chantal

If anyone is still struggling, I just found a solution (not having an alias like many other contributors but just one main address): I simply changed my password via the online space in the "My Account" section at the top right. You just need to enter the new password in Thunderbird, replacing the old one, and it works.

Successful operation for the Huawei Psmart 2019 Android smartphone.
First solution, manually configure as soon as this option appears.
Add an account "enter the alias name" then password to validate the incoming IMAP server.
Then configure the outgoing SMTP server by assigning it the name of the main account.

Second solution is to configure everything with the main account automatically, then modify the reception settings (synchronization options). Change the username by replacing it with the Alias.

Solution found for Thunderbird
Go to account settings.
Select the "alias" account in question.
At the bottom of the window, click Modify SMTP Server
In the new small window that opens, replace the username "alias" with the main account's name.
And it works for me.

Thank you for your response and your advice on the aliases. I had exactly the same issue sending from Thunderbird (68.5.0) with the smtp server of laposte.net. Since the end of January, it no longer recognized the alias I commonly use for the identifier and displayed an unexplained error message!

With version 68.4.2 it works for me. However, I modified the SMTP server settings to use my main address (I have been using an alias for years without any issues).

I have the same error.
Using the main address in the SMTP settings seems to work, but then Thunderbird gets stuck at 95-99% when trying to copy the message to the sent folder (which makes it impossible to be sure if it was sent correctly).

-UPDATE-

Apparently, it was related to Thunderbird; I had the same issue with other servers (Gmail, work...).
I applied the update and everything is resolved.

I have had the same problem for a few days. I just installed the Thunderbird update, I now have version 68.4.2 and sending messages still crashes on smtp.laposte.net with the same error 80004005.

Hello Lucas,

"- username: [the part before the @ of my main address]"

Try using the full email address instead of just the part before the "@"

Same reactions since this week with Thunderbird, even updated with an Alias for a poste.net account...

I think it's time to ask "laposte.net"
I will try to do it on Monday through "LSF" (I am deaf!)

--
A poor lonesome Debianner....

The same problem has also been happening for several days; it is exclusively related to the .net mail service and their SMTP management. We can no longer send via an "alias" address, neither through a PC Thunderbird email client nor through an Android smartphone email client. The two "outages" occurred simultaneously for me.
I tried to communicate with the mail service using the address webmaster"at"laposte.net, which no longer works and redirects us to their "completely unresponsive" online help. Since it refers to obvious outages, our case doesn't fit into the criteria... I fear that the only solution left is to send a paper letter.

Same for me! Outrageous!

Thank you, JLHO!
Indeed, I had this issue for almost a month and couldn't find a solution. I kept running into the complexities of the customer service form, asking for information as "incomprehensible" to the average user as the IP address and the system log file—all for a simple SMTP error. This failure occurred spontaneously when I hadn't changed anything in my configuration: something must have changed in the SMTP server configuration, and we weren't informed about it. Indeed, for the username in my SMTP configuration, I had used an alias. By replacing it with my username as you advised, the problem was resolved like magic. So, THANK YOU!

Even though I haven't questioned "laposte.net" about this issue, I have a feeling that now the "aliases" depend directly on the main address, so it’s the same for the SMTP server.
That being said, I would have liked to know "laposte.net"'s opinion on this subject. It would be nice if they warned us about their changes. They just changed the "login" screen. But that’s only the visible part.

--
A poor lonesome Debianner....

After a final round of corrections yesterday Saturday, it seems that "laposte.net" has fixed the problem with SMTP and the aliases.
To be confirmed

--
A poor lonesome Debianner....

Hello,

Receiving Thunderbird OK - Sending KO (note recent update of Thunderbird to 68.5.0)

Solution:

1- Solution with "Main Address" instead of "Alias" had no effect...
2- Login to the main site "Laposte.net" with the original password... then change the password in "My account" to 11 characters and a * (my original password being much longer and more complex!...)
3- In Thunderbird, delete the saved password (Tools\Options\Security\Passwords...)
4- Return to Thunderbird then confirm the new password with saving (incoming and outgoing)
5- Tested sending and it works! ...
Probably a problem following an update on password management (special characters, length, etc.)
I will test...later...saving a stronger password! ...

Addendum at 05:35

Noticing that I had done tests with my main account in Thunderbird (SMTP account settings), I wanted to put my "Alias" back, and there "oops!", error again on test sends...

I had to re-confirm the new password twice to "force" the identification and therefore establish that the chaining does not work between the main account and the "Alias" (is this normal? well, I don’t know...)

Hello,
I just had to change the password and it works again!