Facing "temporarily unavailable" issue on Backoffice

[d2o]

Hi guys,

Today, I updated a Prestashop installation from 8.2.3 to 9.0.2. Since then, most of the time, when browsing the Backoffice, I will see the following message:

"The page you are looking for is temporarily unavailable. ..."

Until now, I could not figure out anything causing this. In the PHP logs, there are some Deprecated messages, but that's it. Switching the shop to Debug Mode (via SFTP, switching on all debug info) does not help either. 

The Frontoffice is running fine and smooth (currently in Maintenance-Mode). It's only the Backoffice.

Any suggestions on where to look or what to try out are most welcome. I would be very unhappy, if I have to go back to 8.2.3 to have a working shop. Especially, as IONOS will soon start charging for the use of PHP 8.1.

Thanks,
Stefan

Hoster: IONOS
PHP: 8.4
Prestashop: 9.0.2

[juanrojas]

Hi, try enabling debug mode to see if it shows anything.

2. Don't work with IONOS

[d2o]

Hi,

as mentionend, debug is already active. Except for some deprecation messages, there is nothing to see here.

Ad 2.) Not my choice, I am only maintaining the application. 🤷

Cheers,
Stefan

[juanrojas]

It would be interesting to see what it shows you in debug mode, but if you say it's not important, I'd say this is a problem with your server. If you can rule it out with another one, try it.

[d2o]

Well, the only failing thing I see are AJAX-calls to https://api.segment.io/v1/i, which are blocked. Not sure, where these come from.

Seems, I need to contact IONOS for this one. And they will say "We don't support custom web-apps". *sigh*

Cheers, Stefan

[PrestaHeroes.com]

You did nothing wrong. The problem is that PrestaShop 9.0.2 should never have been presented as a safe upgrade path.

Unfortunately, PrestaShop has a long history of publishing major releases as “current” while they are still effectively beta, and PS 9.0.x is a textbook example of this. Merchants upgrade in good faith, only to discover afterward that they’ve become unpaid testers.

Why your upgrade failed

• PrestaShop 9.0.2 is not production-ready:
• Core regressions still exist
• Module and theme compatibility is incomplete
• Critical workflows (checkout, localization, carrier logic, overrides) break silently
• Error handling assumes developer-level debugging skills

This is why even now, newer PS9 releases are labeled beta / for advanced users. That disclaimer came after many merchants were already burned.

What you should do now (important)

• Restore your shop immediately to your last stable backup (PS 8.x or earlier).
• Do not attempt further fixes on PS 9.0.2 — you will only waste time and money.
• Continue operating on PrestaShop 8 (latest stable 8.x), which is production-proven and fully supported by the ecosystem.
• Wait for a genuinely stable PS9 release (not a “current download”, not a beta, not community-tested).

[d2o]

Ok, that does not sound good. Actually, downgrading to 8 is no good option, as IONOS is going to charge for running PHP 8.1 from February on. And, as far as I can see, Prestashop 8 only is compatible with PHP 8.1 at max. 😣

Cheers, Stefan

[matin42]

That “temporarily unavailable” message on the forum Backoffice is usually related to the forum platform itself, not the product you’re asking about. A few things you can try:

Log out and back in, or open the forum in an incognito/private window to clear session issues.

Check if the forum has a status/announcements section — many communities post when Backoffice or moderation tools are under maintenance.

If you’re trying to edit or manage your post, make sure your account permissions allow Backoffice access (some forums restrict it to moderators or higher trust levels).

If it keeps happening, tagging a forum moderator or admin is usually the fastest way to confirm whether it’s a platform outage or a permission issue.

[Ray UK]

20 hours ago, d2o said:

Ok, that does not sound good. Actually, downgrading to 8 is no good option, as IONOS is going to charge for running PHP 8.1 from February on. And, as far as I can see, Prestashop 8 only is compatible with PHP 8.1 at max. 😣

Cheers, Stefan

Prestashop works higher than 8.1
This is my install on 8.2.30

[d2o]

1 hour ago, Ray UK said:

Prestashop works higher than 8.1
This is my install on 8.2.30

Great, Thanks. I might try that one. Would buy a year.

Cheers, Stefan

[clemmiejoules]

This is a common issue after upgrading to PrestaShop 9.x. In most cases it’s caused by OPCache or stale Symfony cache rather than a real outage. Try clearing /var/cache/* manually and disable or relax OPCache (very common on IONOS). Also make sure you’re running PHP 8.1 and that all modules are PS9-compatible. If the Back Office stabilizes with modules disabled, one of them is the culprit.

[PrestaHeroes.com]

On 1/20/2026 at 10:17 AM, d2o said:

Ok, that does not sound good. Actually, downgrading to 8 is no good option, as IONOS is going to charge for running PHP 8.1 from February on. And, as far as I can see, Prestashop 8 only is compatible with PHP 8.1 at max. 😣

Cheers, Stefan

Hey Stefan,

You are currently with what I would call “pirate hosting” — the type of provider that dictates which PHP versions you are allowed to run and can just as easily auto-upgrade PHP without notice, breaking your shop overnight.  Over my many years of helping in the forum I have seen 100's of instances of where hosting upgraded the php to level not supported by PS.  But there were many that did not post here, that's ridiculous. 

A proper setup is one where you control the PHP environment. That is exactly what you get with a VPS using Plesk: you decide which PHP versions are installed, which one each domain uses, and nothing changes unless you change it.

If a host is charging you extra just to choose or lock a PHP version, that should already be a major red flag. If they will nickel-and-dime you over PHP, imagine what else they are doing behind the scenes — none of it is good.

Hosting providers should never dictate your PHP runtime. Unfortunately, many modern hosts build their own “custom” control panels with artificial constraints. This always comes back to bite merchants. I have seen countless shops on this forum go offline after a new PHP version is released and the host rolls it out globally across all accounts. At that point, you are not a customer — you are a beta tester.

My honest advice: run away from IONOS.

Even OVH — despite its own historical issues — at least allows you to run a proper VPS with NVMe SSD and Plesk, where you stay in control. That said, I do not recommend OVH for U.S.-based users due to their strange support and contractual limitations.

Best option is to get a US bases VPS with Plesk, we have big fat fiber pipes to other world  and IP is no longer part of seo  (i.e. localization) just the domain cctld/gtld.

Bottom line:
If your host controls your PHP, your shop is living on borrowed time.  

 

 

Edited Wednesday at 10:18 PM by El Patron (see edit history)

[d2o]

13 hours ago, clemmiejoules said:

This is a common issue after upgrading to PrestaShop 9.x. In most cases it’s caused by OPCache or stale Symfony cache rather than a real outage. Try clearing /var/cache/* manually and disable or relax OPCache (very common on IONOS). Also make sure you’re running PHP 8.1 and that all modules are PS9-compatible. If the Back Office stabilizes with modules disabled, one of them is the culprit.

Thanks. I will check for the OPCache. Already cleared the /var/cache several times 😄 And I might try with disabled modules, too. Although this rather looks like some Webserver issue with a 504. Unfortunately, I seem not to have access to error logs with that hosting.

Cheers, Stefan

[d2o]

8 hours ago, El Patron said:

My honest advice: run away from IONOS.

I would, if I could. It's not my decision to make. I only support and advice but do not run the shop. 🤷

Cheers, Stefan