Error Page after submitting message

Hi,
after submitting a message via reservation and contact forms i always got an error page with code 0 and "INVALID ADDRESS:".
and the mail could not be sent.
I got no idea what the problem is, cause i installed qucikstart-package and changed nothing special in settings.

Thanks for Help!

Hello,

Please try to redownload the rest_files package for your template and reinstall the reservation/contact plugins - we have released a fix for it due Joomla! 3.5.1 API breaking changes: https://www.gavick.com/updates?task=upd ... 49&catid=4

Perfect, thank you for help!
So reservation and contact-form in footer area are working fine now:-)