Automatically created images in blogView are not shown

I have a really great problem with Template Blog Category view.
I use it with automatically generated images. Value imagesource was set to "Extract from Description", position left, imagesize Parameter, height and width 200px, processing method scale.

My problem was that sometimes -and not really reproducable- the automatic generated images are not shown.
The view shows then a coloured square with an red text "Error message disabled".
The sourcecode of these section in that situation (customer send it to me) shows -for me- nothing conspicuous.

Here the screen.[attachment=0:8c7ywj5h]<!-- ia0 -->sreenshot.jpg<!-- ia0 -->[/attachment:8c7ywj5h]

Has anyone an idea what's going wrong here? Because i get a lot of pressure from customer

hello
do you check your folder permission (for thumbmail) ?

the folder /html/components/com_flexicontent/librairies/phpthumb
was still under 777.

Interesting was that these was not a permanent problem.
I discuss with my hosting provider if f.e. we have a problem with php-memory-cache, but he checks the logs and found no situation where we come to the limit.

we found the usecase to reproduce it:

if we go in the system with the major URL
www.ostwestfalen-lippe-socialmedia.de
works all ok.
But these website was also reachable over additional url's and there these error happens.
web72.server10.dmsoltutionsonline.de

Could be possible that the generation of images only work correctly with the url wich are placed in joomla configuration file as $live_site?