[TYPO3-english] Validating the security token of this form has failed issue in flexform with over 45 section entries

[Domi]

Hello,

I just made a Flexform based FCE with section objects. The element works 
very well. But if I include more then 45 elements, the whole flexform 
element breaks with following error:

Validating the security token of this form has failed

Is there a limitation inside TYPO3 regarding to:

form processing / flexform handling / token protection?

Would be great if someone can give me an idea how to solve this. I run 
my TYPO3 package on hosted server, so its not possible to adjust 
max_post_size, if this would matter anyhow.

Best Regards,

Dominic