About private message feature in the forum

Dear Admin,

I have the problem of wanting to send private messages to any account, specifically Admin,
But I can't find any place to contact in the forum except to post on my personal profile
When I click reply to a post on my profile, the system gives me an error message that I can't do it

P/S: I hope the admin has a specific answer about the problem I have messaged in your profile poste, thank you

Best regards,

Cao Chanh Khai