Prestashop 9.0 - fresh installation - error 500 on admin login

[Marek_G]

Just received error 500 when attempting to login to admin panel - presta 9.0 fresh installation.

In dev/logs/ got warnings and errors as in attached log file.

 

error.log

[compsoul.dev]

Are the errors complaining about a missing theme folder? How did you transfer everything? Do you have the correct file permissions? If not, try copying admin/themes/default manually. Where did you get the installation package from? How are you uploading it to the server? What PHP version are you using?
Also, please don’t upload logs as a downloadable file my firewall throws a warning when I try to access them.

[Marek_G]

Hi.

This is main part of the log 

[2025-06-16T10:43:34.979484+02:00] request.CRITICAL: Uncaught PHP Exception Twig\Error\LoaderError: "The "/home/host810499/domains/ip20.pl/public_html/admin/themes/new-theme" directory does not exist ("/home/host810499/domains/ip20.pl/public_html/admin/themes/new-theme")." at FilesystemLoader.php line 99 {"exception":"[object] (Twig\\Error\\LoaderError(code: 0): The \"/home/host810499/domains/ip20.pl/public_html/admin/themes/new-theme\" directory does not exist (\"/home/host810499/domains/ip20.pl/public_html/admin/themes/new-theme\"). at /home/host810499/domains/ip20.pl/public_html/vendor/twig/twig/src/Loader/FilesystemLoader.php:99)"} []

[2025-06-16T10:43:34.988012+02:00] request.CRITICAL: Exception thrown when handling an exception (Twig\Error\LoaderError: Template "@PrestaShop/Admin/Error/error.html.twig" is not defined. at ChainLoader.php line 111) {"exception":"[object] (Twig\\Error\\LoaderError(code: 0): Template \"@PrestaShop/Admin/Error/error.html.twig\" is not defined. at /home/host810499/domains/ip20.pl/public_html/vendor/twig/twig/src/Loader/ChainLoader.php:111)"} []

[2025-06-16T10:43:34.988086+02:00] request.CRITICAL: Uncaught PHP Exception Twig\Error\LoaderError: "Template "@PrestaShop/Admin/Error/error.html.twig" is not defined." at ChainLoader.php line 111 {"exception":"[object] (Twig\\Error\\LoaderError(code: 0): Template \"@PrestaShop/Admin/Error/error.html.twig\" is not defined. at /home/host810499/domains/ip20.pl/public_html/vendor/twig/twig/src/Loader/ChainLoader.php:111)\n[previous exception] [object] (Twig\\Error\\LoaderError(code: 0): The \"/home/host810499/domains/ip20.pl/public_html/admin/themes/new-theme\" directory does not exist (\"/home/host810499/domains/ip20.pl/public_html/admin/themes/new-theme\"). at /home/host810499/domains/ip20.pl/public_html/vendor/twig/twig/src/Loader/FilesystemLoader.php:99)"} []

[2025-06-16T10:43:34.988226+02:00] request.CRITICAL: Exception thrown when handling an exception (Twig\Error\LoaderError: Template "@PrestaShop/Admin/Error/error.html.twig" is not defined. at ChainLoader.php line 111) {"exception":"[object] (Twig\\Error\\LoaderError(code: 0): Template \"@PrestaShop/Admin/Error/error.html.twig\" is not defined. at /home/host810499/domains/ip20.pl/public_html/vendor/twig/twig/src/Loader/ChainLoader.php:111)"} []
 

 

About installation - get presta 9.0 from prestashop.com downloads (prestashop_edition_basic_version_9.0.0-1.0), unpacked locally and get 3 files index.php, prestashop.zip and Install_Prestahop.html. Then go to browser Chrome and put main domain address ip20.pl - everything standard, nothing special.

Then, after successful installation i try to go to shop frontend - it works. then i try to go to admin panel - got 500 html error. You can see what is in log .

 

Its simple : "/home/host810499/domains/ip20.pl/public_html/admin/themes/new-theme" directory does not exist - yes, "admin" folder dosnt exists as it has different name - "admin....." . In the "admin....." directory i got this /themes/new-theme .

No matter what PHP version 

Marek

[compsoul.dev]

- It looks like PS has incorrectly set the admin path. Please check:
- The admin folder name via FTP. It should look like: admin123abc
- Verify that there is no directory named admin in the shop’s root folder.
- Check app/config/parameters.php to ensure there's no incorrect admin path.
- Delete the cache directories: /var/cache/prod/ and /var/cache/dev/
- Check this link: https://github.com/PrestaShop/PrestaShop/issues/38859

[Marek_G]

Hi. there is nothing about admin path in app/config/parameters.php

I cleared the cache and it works, thank you.

Marek

[DG Dreams]

Sorry to hear you're running into this on a fresh install. Error 500 usually points to a server-side issue most often related to file permissions, missing PHP extensions, or issues in the .htaccess file. Since you're seeing errors in the dev/logs/, those logs should give some clues. I'd recommend enabling debug mode in config/defines.inc.php to get a clearer error message on screen. Also, double-check PHP version compatibility with PrestaShop 9.0 and ensure all required modules are installed. Let us know what the log says happy to help further.