we moved our magento shop to another hosting and now visitors, who use the contact form, get an error message, even though the e-mail is sent successfully.
We didn't change anything in the core files or the template files of the contact form.
The hosting provider told us, that is has to be an error or bug in magento.
I thought about editing the core files, which produce that error, but that would not be a good idea in my opinion, because there is obviously something going wrong.
Did anyone of you run into a similar problem?
Error Message (English):
Unable to submit your request. Please try again later.
Thanks to the hint from Fabian Blechschmidt, I found the exact exception:
Unable to send mail. mail(/var/log/mail.php.log): failed to open stream: Permission denied
Even though chmod 777 was set for the log-folder, magento can't create the "mail.php.log"-file on the server. But why?
It turned out that the path "/var/log/" does not mean the path from the magento root, but from the apache root. Therefore, the folder "/var/log" does not exist and can not be created by PHP.
This path is defined by the "mail.log" value in the php.ini. Because I don't need any tracking of mails sent by the server, I just removed this value and everything is working as expected now!
It was no magento-problem, but a wrong server configuration.
Once again, thanks everyone!