Troubleshooting für Magento Extensions

Magento ist ein komplexes System, in dem viele verschiedene Fehler auftreten können. Sollten Sie nicht mehr weiter kommen, ziehen Sie mich gerne als Experten hinzu.

Auf dieser Seite möchte ich einige Möglichkeiten aufzeigen, was geprüft werden kann, wenn Fehler in Magento oder nach der Installation von Magento Extensions auftreten.
Außerdem zeige ich einige häufige Fehler, die sehr oft im Support bei meinen Kunden vorkommen.

Cyrillic characters are displayed as "?" on the Magento PDF invoice. What can I do?

The problem is that the chosen font family does not support the Cyrillic characters. So far no font with Cyrillic support is included into the Advanced Invoice Layout Extension. That means that you have to get your own font family with support for Cyrillic characters and include it into the Advanced Invoice Layout Extension.

Please also see my FAQ article about adding a new font.

Error message "Mage registry key already exists" e.g. after extension installation
See here.
I cannot login to the Magento Admin - what can I do?

Sometimes you have the problem that you cannot login to the Magento Admin area - despite entering the correct username and password. There are several points that you can check in this case (it is most probably an issue with the cookies):

  • Check the cookie domain in the core_config_data table that it matches your backend domain
  • Also check that if you previously switched from HTTPS to HTTP that you drop all browser cookies, as if the adminhtml cookie already exists with the "Secure" flag, it cannot be overwritten
I get a "404"-Error after the installation of the extension
Symptom: A 404 error is shown if you go to System › Configuration and choose e.g. Advanced Invoice Layout tab.

To solve this kind of error you need to log out of the backend and log in again. Then the tab should be successfully accessible.
I get the error message "There has been an error processing your request". What can I do?

The error message "There has been an error processing your request" is one of the most frequent error messages in in Magento 1 and Magento 2. This message is displayed in general if an error of any kind has occurred in Magento.

In this case Magento creates a file with the name of the error report number in the directory var/report, that contains further information regarding this error.

Please find an example for the error in the following screenshot:

Magento: There has been an error processing your request

Afterwards we check the contents of the file var/report/var/report/71f20cdad8ceb5efde802084ba1eec158275937c822322eee3b1eac5ebde00b0 in our Magento root directory for the sample error:

  "0": "test",
  "1": "#1 Composer\\Autoload\\includeFile('\/home\/vianetz\/ma...') called at [vendor\/composer\/ClassLoader.php:322]\n#2 Composer\\Autoload\\ClassLoader->loadClass('Magento\\Framewor...')\n#3 spl_autoload_call('Magento\\Framewor...')\n#4 is_subclass_of('Magento\\Framewor...', '\\Magento\\Framewo...') called at [vendor\/magento\/framework\/ObjectManager\/InterceptableValidator.php:42]\n#5 Magento\\Framework\\ObjectManager\\InterceptableValidator->isInterceptable('Magento\\Framewor...') called at [vendor\/magento\/framework\/ObjectManager\/InterceptableValidator.php:16]\n#6 Magento\\Framework\\ObjectManager\\InterceptableValidator->validate('Magento\\Framewor...') called at [vendor\/magento\/framework\/Interception\/ObjectManager\/Config\/Developer.php:62]\n#7 Magento\\Framework\\Interception\\ObjectManager\\Config\\Developer->getInstanceType('Magento\\Framewor...') called at [vendor\/magento\/framework\/ObjectManager\/Factory\/Dynamic\/Developer.php:47]\n#8 Magento\\Framework\\ObjectManager\\Factory\\Dynamic\\Developer->create('Magento\\Framewor...') called at [vendor\/magento\/framework\/ObjectManager\/ObjectManager.php:70]\n#9 Magento\\Framework\\ObjectManager\\ObjectManager->get('Magento\\Framewor...') called at [vendor\/magento\/framework\/App\/Http.php:115]\n#10 Magento\\Framework\\App\\Http->launch() called at [generated\/code\/Magento\/Framework\/App\/Http\/Interceptor.php:24]\n#11 Magento\\Framework\\App\\Http\\Interceptor->launch() called at [vendor\/magento\/framework\/App\/Bootstrap.php:261]\n#12 Magento\\Framework\\App\\Bootstrap->run(&Magento\\Framework\\App\\Http\\Interceptor#000000006a1e7d590000000079678f99#) called at [index.php:39]\n",
  "url": "\/",
  "script_name": "\/index.php",
  "report_id": "71f20cdad8ceb5efde802084ba1eec158275937c822322eee3b1eac5ebde00b0"

If you do not find a solution for your problem, just send us this file please.

Magento shows a Blank Page

While executing some actions Magento is only showing a blank page without any content.
This behaviour is mostly caused by a Fatal PHP error. Please have a look into your PHP log files (perhaps ask your hoster) and/or see the Magento error log in the directory var/log of your Magento installation.

PDF documents cannot be generated when using a PDF background template file
Solution: Try to save the background PDF template file, especially save the PDF as PDF/A for Acrobat 1.4 or Acrobat 5.