Exporting Large (26MB) Calendar hangs out

Exporting calendars works fine, almost with everyone. There is one, the biggest that hangs out.
I could export it only using calcardbackup through command line. But trying to export it by User Interface it hangs out, actually after 8 min or so it appears Error 500.
Large (26MB) Calendar.

You have to check if there is a php timeout, webserver timeout, database timeout … or some memory limits, …