I have a 500 error (unable to connect to the server 500 error) in the backend of Sendcloud (shipping module) if I try to connect to the Prestashop server.
If debug modus in ON, the request of Sendcloud goes fine. (???)
I also get a 500 error in the backend when I try to clear the cache.
The 500 error is not 100% persistent! (+ 80% of the time).
If I reload the page with the 500 error (1 or 2 times) the request to clear cache passes (about +90% of the time).
A couple of time I had a white screen and I was unable to login to the backend. (needed to change config file or do a complete backup)
Frontend keeps working ok, while having 500 errors in backend.
What I tried:
Contacted my hosting hosting provider and they researched the server.
They could not detect a server issue.
In the error logs they could see the following error:
------
error.log.1.gz:[Thu Apr 18 14:15:37.817149 2019] [error] [pid 23339] mod_proxy_fcgi.c(860): [client IP ADDRESS ] AH01071: Got error 'PHP message: PHP Fatal error: Interface 'PrestaShop\\PrestaShop\\Core\\Grid\\Query\\DoctrineQueryBuilderInterface' not found in /data/sites/web/mywebsiteeu/www/src/PrestaShopBundle/Entity/Repository/RequestSqlRepository.php on line 38\n'
----
I checked and the file 'DoctrineQueryBuilderInterface.php' is in directory
/www/src/Core/Grid/Query
RequestSqlRepository.php states on line 31
"use PrestaShop\PrestaShop\Core\Grid\Query\DoctrineQueryBuilderInterface;"
When working in debug modus after a couple of trials, I finally got 1 debug error:
----
Compile Error: ContainerUt0lms3\appDevDebugProjectContainer::load(): Failed opening required '/data/sites/web/ website eu/www/var/cache/dev/ContainerUt0lms3/getPrestashop_Module_Zip_ManagerService.php' (include_path=‘/data/sites/web/ website eu/www/tools/htmlpurifier/standalone:/data/sites/web/otsudreamseu/www/vendor/pear/pear_exception:/data/sites/web/ website eu/www/vendor/pear/console_getopt:/data/sites/web/ website eu/www/vendor/pear/pear-core-minimal/src:/data/sites/web/ website eu/www/vendor/pear/archive_tar:.')
---
Aftre checking the forum I deleted
dev & prod directories and files in path => /www/var/cache/
but this makes no difference.
I enabled and disabled smart cache, but the error persists.
PrestaShop version: 1.7.4.2
Server information Linux
Server software version: Apache
PHP version: 7.2.15
Memory limit: 256M
Max execution time: 300
Upload Max File size: 256M
Datbase: MySQL version: 5.7.22-22
Anyone the encountered this problem yeT
Please can someone advice or help me?
Thanks in advance!