Strange problem with web.xml - no idea

[defpl]

Hello, since 2019 I have Prestashop 1.7.5.0.

Generally everything worked, I didn't update or touch anything, the server is a VPS so the PHP 7.2 version has remained unchanged.

However, recently I wanted to upload a new module and after uploading it everything... crashed. That is, the frontend works but the admin panel threw an internal server error 500 (error in the attachment).

It couldn't be saved, the administrator who manages the server couldn't either.

We restored /var/cache from the backup and... everything went back to normal. All I have to do is change anything that changes /var/cache and it crashes.

I decided to migrate to 8.2 but I can't even upload the connector for transferring because everything crashes... There is no information about this problem in Google.

I recompiled composer dump-autoload and copied the entire /vendor/ directory but no changes - the problem still exists.

[ComGrafPL]

Disable cache and external modules. Retry with installing connector. Make sure connector is also for 1.7 not for 8+.

[defpl]

Unfortunately I first tried to remove modules - the first one was removed, the second one the endless removal icon and... the same problem, the whole Presta from the admin panel side crashed.

I changed the php version to 7.0 and it didn't help either.

[El Patron]

What is happening:
Your PrestaShop admin is broken due to a corrupted or invalid Symfony XML configuration, likely triggered by a recently uploaded module. The error references /vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/Resources/config/web.xml and happens whenever the cache is rebuilt. Restoring /var/cache is only a temporary fix.

Suggest fix:
(You did not supply the name of the module you uploaded—this information is very important for others to help you quickly!)

1. Rename the last module you uploaded via FTP (and review overrides):

• Go to /modules/ with your FTP client.
• Find the folder for the last module you installed (the one before the crash).
• Rename the folder from modulename to _modulename. This “disables” the module without deleting anything.
• Important: Many PrestaShop modules create override files in /override/. Even if you rename the module folder, any override files it added might still be active and cause errors.
• Review the /override/ folder for any recently changed files (often named after the module or its features).
• Temporarily rename or move any suspicious override files or folders (e.g., CartController.php → _CartController.php).

2. Clear the cache:
Delete both /var/cache/dev and /var/cache/prod.

3. Reload your admin panel:

• If the admin loads, you’ve found the culprit.
• If not, check for other recently changed module folders or overrides and repeat the process.
• You can also look for custom config files (XML/YAML) in /modules/, /app/config/, or /override/ and try renaming those.

4. If you still have errors related to web.xml or other files in /vendor/:

• Restore the original /vendor/ directory and core Symfony XML files from a fresh PrestaShop 1.7.5.0 archive.
• Do not rename or delete files in /vendor/. If any are corrupted, overwrite them with the originals.

Notes:

composer dump-autoload won’t fix corrupted config files or module errors.

Don’t try to upgrade or change versions until your admin is working again.

If you need to migrate to a new shop, always start from a clean, stable backup.

Let us know which module caused the problem—often the community can help even faster if they know exactly what you installed!

[defpl]

Yes, because I recently sent a module that supposedly didn't break anything - according to this company, this defect was there before.

I did what you said

1. I removed all modules from external companies via FTP, they were not visible in the Prestashop panel.

2. I only had 28 files in the override but I didn't see that any of them were responsible for anything, so I didn't touch anything here.

3. I deleted the cache and... the problem returned.

I overwrote the entire /vendor/ directory before, but also without success.

At the moment, all I want to do is upload the connector and transfer orders, customers (without modules) to the new Prestashop 8.2 Unless there are some plugins that will transfer it e.g. via API? Or directly from the database dump?

[El Patron]

Hey @defpl  contact @musicmaster he has a lot of experince including mdoule method....that's who I would  go to on the fourm for migrating data but given you don't have admin...I think he can still give good advice.

[Krystian Podemski]

Hello

It may be related to problems with permissions or missconfiguration of the /tmp directory on your new server.