When answering a SF message, I get an error

[albertzeyer]

The error message:

There was an error processing your request ...

Error - Missing Params
ERROR - Missing Required Parameters.

[ctsai]

Hello,

Can you provide more context? Where exactly are you seeing this? What are you trying to do?

Thanks,
Chris Tsai, SourceForge.net Support

[albertzeyer]

I got a mail from a user via the SF message form (btw, very annoying, I want my users to just email me but I didn't found a way to just put an email there and to disable the SF messaging).

There was no way to directly answer the mail (also very annoying; I remember that there was a way to register a mail account somehow to do that but also had trouble in most cases with it; anyway, this time, it came from noreply@…)

The mail had this as the bottom:

This message was sent to your SourceForge.net email alias via the web mail form. You may reply to this message via https://sourceforge.net/sendmessage.php?touser=3712858 .

And there, after writing my answer and clicking 'Send message', I got this strange, not really helpful, error.