does anyone know why I cannot message other providers?

We can't really answer because we don't know which site you're talking about; some have their own messaging system and others would need you to send a direct email or a text if you want to contact somebody specific.

If you're talking about here, you need to participate on the forum before you get access to the PM system. We can't have all and sundry signing up just to pester the members here (many of whom are new and some vulnerable) via a method qhich we can't easily keep track of, as I'm sure you understand.

We also don't want threads about the forum on the forum, because it's off topic and nothing to do with sex work

There are no 'girls' here, at least hopefully not.

SAAFE has always been primarily aimed at newbies - many of whom have yet to start or put up ads - although all sex workers are welcome. There is no way to check anybody's credentials (even if we did have the time and resources to poke about online all day), and there are no 'right' reasons for anybody being here provided they are a sex worker who wants to discuss/ask questions about/share experiences of sex work.

Questions about sex work are what the Questions and Answers forum is for; as per the rules, if you have a query about the site or forum itself, feel free to email the SAAFE admin address with it. If you are asking specifically about the PM system here, access is gained by contributing to the forum as above. There are currently 43,391 topics on the board, most of which can be posted in, so crack on.

Since it's off topic, pointless and going round in circles, this topic is locked.