Warning: Cannot modify header information

[DirkS]

Hi beautiful human beings,

after migration I try to get the shop (Version 1.7.4.4) of a friend working. Problems occurred right after the migration with images not showing and some problems with some white pages in backend. So I enabled debug modus an the following message showed up:
 

Quote

(1/1) ContextErrorException

Warning: Cannot modify header information - headers already sent by (output started at /www/htdocs/w019d29d/kinderzimmertextilien.de/config/defines.inc.php:45)

in FrontController.php line 934

at FrontControllerCore->initHeader()in Controller.php line 251

at ControllerCore->run()in Dispatcher.php line 428

at DispatcherCore->dispatch()in index.php line 28

 

I'm new to Prestashop. Any ideas?

Thanks for your help, Dirk

Edited November 7, 2019 by DirkS (see edit history)

[selectshop.at]

Welcome to Prestashop Forum. Did you try to search for the problem you are having ? There are several topics/posts treating this same problem. Not specific to PS 1.7.4. because it is a  common problem of a bad coded file, in general non default one. Disable all non-standard Prestashop modules, disable overrides. If you are using a non default template, than disable it and use the default one. This error is due to an override or some wrong changed thing you are using.

 

[DirkS]

Thank you for your quick response.

Sadly, the links you posted here do not offer solutions. I tried to google before and of course I checked this forum before opening a new thread. 

Regarding your thoughts: I could disable every paging mod if I would be able to access the modules settings in backend. But it's not possible - white page. 

 

[PCQUATRO]

1 hour ago, DirkS said:

Thank you for your quick response.

Sadly, the links you posted here do not offer solutions. I tried to google before and of course I checked this forum before opening a new thread. 

Regarding your thoughts: I could disable every paging mod if I would be able to access the modules settings in backend. But it's not possible - white page. 

 

First i would try to clear the cache using FTP, deleting /var/cache/*. Than if it does not solve the problem, comment lines mentioned in the error 1 by one and try to enter the BackOffice, if that does not let you in, try renaming the files mantioned one by one and test the BackOffice… if and when you manage to enter the BackOffice, as suggested, try to disable everything that was added to the shop...

BUT ALLWAYS BACKUP FIRST...

Best Regards

[JBW]

You can deactivate doubtful modules / override by renaming them on FTP to xx_old