Issue Preferred Domain & Alias Redirect behavior inconsistent after recent updates

[Shibumi]

Server operating system version

Ubuntu 20.04.6 LTS, Ubuntu 22.04.5 LTS

Plesk version and microupdate number

Plesk Obsidian 18.0.77 Update #2

Hello,

I’m currently observing inconsistent redirect behavior in Plesk, which seems to have started only after recent updates.

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Environment​

• Multiple production Plesk servers
• Servers have been running stable for several years
• Large number of domains (100+) and aliases configured
• Issue observed on 2 servers after recent updates
• Other (not yet updated) systems still behave correctly

Affected systems:

• Plesk Obsidian 18.0.77 Update #2
• Ubuntu 22.04.5 LTS
• Ubuntu 20.04.6 LTS

Webserver setup:

• LiteSpeed Web Server in production
• Issue also reproduced with Apache-only mode

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Observations​

1. Preferred Domain setting is no longer enforced
   • Without aliases → works as expected
   • As soon as an alias is added → preferred domain redirect stops working completely
     
2. Alias redirect option not working
   • When enabling "Redirect with the HTTP 301 Code" on an alias
   • The visitor is still served the website instead of being redirected to the main/preferred domain
     
3. Regression after update
   • This behavior did not occur before
   • Only started after recent Plesk updates
   • Older systems with identical configuration still behave correctly

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Expected behavior​

• Preferred domain (www vs non-www) should still work even when aliases are configured
• Alias redirects should properly redirect to the main or preferred domain when
  "Redirect with the HTTP 301 Code" is enabled

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Impact​

• Long-running setups suddenly changed behavior after update
• SEO-relevant canonical redirects are no longer applied
• Existing configurations became inconsistent

To maintain expected behavior, we had to introduce rewrite rules to enforce the preferred domain setting (www or non-www) depending on customer configuration.

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Questions​

1. Is this behavior intentional or a regression/bug?
2. If intentional:
   • What is the reasoning behind disabling preferred domain redirects when aliases exist?
3. If not:
   • Is there already a known issue or fix planned?
4. Where is the canonical redirect logic handled internally in current versions?

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Has anyone else observed similar behavior after recent updates, or can provide some insights?

I’m happy to share additional details (versions, configs, etc.) if needed.

Thanks in advance!

 

[Sebahat.hadzhi]

Thank you for the report, @Shibumi . There's already a bug (ID PPPM-15356) registered for the reported issue with the alias redirect. Our team is working on introducing a fix. The same should be released along with Plesk Obsidian 18.0.78. You can monitor the changelog here. I will open an internal report for the preferred domain issue and will follow-up with more details as soon as possible.