Issue 421 Misdirected Request

[PalmtreeRoundabout]

Server operating system version

Ubuntu 24.04

Plesk version and microupdate number

18.0.71.0

Happened randomly, all sites now receiving 421 Misdirected Request - all via Cloudflare Strict Full with Lets Encrypt SSL.

If I assign the default site under IP Addresses, this site will load fine.

 

[thinkingcap]

I have same issue - just randomly started.
I dont use Cloudflare for anything, certs are Lets Encrypt.

 

[PalmtreeRoundabout]

I have same issue - just randomly started.
I dont use Cloudflare for anything, certs are Lets Encrypt.

There was an update yesterday that was ran, perhaps broken update? Are you running 18.0.71

 

[thinkingcap]

There was an update yesterday that was ran, perhaps broken update? Are you running 18.0.71

Same versions of O.S & Plesk as you.

 

[PalmtreeRoundabout]

Solution:

echo -e "proxy_ssl_server_name on;\nproxy_ssl_name \$host;" > /etc/nginx/conf.d/fixssl.conf && service nginx restart

 

[zvangi]

How was this pushed without noticing it during testing?

 

[danielchau]

I feel disappointed with plesk. This caused us serious outage of many servers.

 

[PalmtreeRoundabout]

How was this pushed without noticing it during testing?

Could be affecting only a specific scenario - our instance was running the updated version for almost 24 hours before it started breaking sites. The fix was published pretty soon after finding the fault.

The resolution wasn't published or hotfix supplied en-masse which further reinforces that it may have been only a small subset of configs that are / where affected.

 

[AlkatraZ]

I have the same problem

 

[GerdSchrewe]

Me too...

 

[Myrlo]

Same problem

The solution above worked

 

[Ahmet CAVUSOGLU]

Hi @PalmtreeRoundabout

It Works!

Thank you so much for sharing your command line. I was on vacation and needed to reboot and repair my system. Thank you so much.

 

[GerdSchrewe]

Thx a lot!

I too can confirm that it works.

echo -e "proxy_ssl_server_name on;\nproxy_ssl_name \$host;" > /etc/nginx/conf.d/fixssl.conf && service nginx restart

 

[AlkatraZ]

The solution proposed above helped! Thank you.

 

[GerdSchrewe]

Does anyone already know why this happened or whether the error might happen again?
I always hesitate for a few days before installing the latest Plesk update because it's often still buggy.
Does 18.0.71 fix the issue?

I have 2 V-Servers at Contabo.
Ubuntu 22.04, Plesk 18.07 Update 2

 

[PalmtreeRoundabout]

Does anyone already know why this happened or whether the error might happen again?
I always hesitate for a few days before installing the latest Plesk update because it's often still buggy.
Does 18.0.71 fix the issue?

I have 2 V-Servers at Contabo.
Ubuntu 22.04, Plesk 18.07 Update 2

The issue is with version 18.0.71 which is A/O right now, still faulty. The issue stems from the Apache foundation, not specifically Plesk itself; as updates are for various components.

I recommend updating to the latest version (for other security fixes) and running the hotfix script.

 

[~ Andrea ~]

Thank you very much @PalmtreeRoundabout

https://support.plesk.com/hc/en-us/articles/33500191748887-Websites-hosted-in-Plesk-are-not-accessible-after-a-recent-Apache-update-421-Misdirected-Request

I've also noticed this recent article.
A.

 

[krisdoff]

Woke up to 3 servers and 150+ domains sending out nothing but the 421 error.

Thanks for the fix provided here that got everything up and running again!

 

[technomatit]

Thank you! @PalmtreeRoundabout you saved my holidays

 

[Krzysztof]

echo -e "proxy_ssl_server_name on;\nproxy_ssl_name \$host;" > /etc/nginx/conf.d/fixssl.conf && service nginx restart

Above solution works.
PLESK 18.0.70 #2

but.... Settings:

• Automatically install Plesk updates (Recommended) - OFF
• Automatically install updates for third-party components shipped by Plesk -OFF
• Automatically install system package updates Note that this will also automatically install updates for third-party components shipped by Plesk - OFF
• Access Plesk Installer via the Plesk hostname and port Access the Plesk Installer web interface without having to open additional 8447 TCP port in the firewall. - OFF
• Enable safe updates for system packages - ON

Moreover I've received email from plesk panel 2025-07-16 06:25 about new updates available (You propably know that message):
The following package updates are available:
- apache2 2.4.58-1ubuntu8.7 from Ubuntu for noble-updates by Ubuntu repo (currently installed version: 2.4.58-1ubuntu8.6 from now repo)
- apache2-bin 2.4.58-1ubuntu8.7 from Ubuntu for noble-updates by Ubuntu repo (currently installed version: 2.4.58-1ubuntu8.6 from now repo)
- apache2-data 2.4.58-1ubuntu8.7 from Ubuntu for noble-updates by Ubuntu repo (currently installed version: 2.4.58-1ubuntu8.6 from now repo)
- apache2-utils 2.4.58-1ubuntu8.7 from Ubuntu for noble-updates by Ubuntu repo (currently installed version: 2.4.58-1ubuntu8.6 from now repo)

After a minute an (SNI) error occured and above updates were not accessible via plesk update tool (pum) anymore.
However:

#dpkg -i apache2-bin
ii apache2-bin 2.4.58-1ubuntu8.7 amd64 Apache HTTP Server (modules and other binary files)

It seems that this package was automatically updated from: (currently installed version: 2.4.58-1ubuntu8.6 from now repo)

Can anyone confirm the same scenario? For me the issue is not the corrupted package but the autoinstall when i did not ask for that...