Conflict server error on save changes

Dear all

I tried searching on this forum and internet but could not find someone describing a similar problem and solution.
I am pretty new to wordpress so please forgive any newbie mistakes.

Just installed wordpress. Installed the latest qTranslate-X from wordpress. activated the plugin. Added the language “Europe and USA” ans switched the default language from GB-Englisch to Europe. When I then try to save the changes I get the following error message:
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, [email protected] and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.

I already tried to remove qTranslate and install the latest version from GitHub (download as zip and upload from within wordpress). That version however doens’t work correctly form me. It somehow doesn’t display the settings page correctly.

Any idea why I get the server error and how to solve this?

Thanks in advance.

https://ww.wp.xz.cn/plugins/qtranslate-x/