In order to send a user a PM you have to be connected to them on the Community. You do this by "following" the user, but then they also must "follow" you in order to allow you to message them. This is a security feature so that no single user could send spam or other messages to those not interested in receiving messages in their inbox. You could reply to one of their threads via the comment section to request they "follow" you - that way you will be able to send them a PM.
Hi -
In order to send a user a PM you have to be connected to them on the Community. You do this by "following" the user, but then they also must "follow" you in order to allow you to message them. This is a security feature so that no single user could send spam or other messages to those not interested in receiving messages in their inbox. You could reply to one of their threads via the comment section to request they "follow" you - that way you will be able to send them a PM.
Hope that helps!