Issue with Buddypress

Basically, we are using a plugin called forminator to do login and registration for our BuddyPress WordPress site. They are sent an activation email that takes them right into the site. What has been happening is that when some of the users that registered they are not getting their activation email and if they try to log in it says their password is incorrect. If we manually activate them and change their password it still says they have the wrong password so we have about 100 users where this issue has happened out the 500 subscribers that have joined as members. And the ones who this is happening to are not assigned “participant” as forum role. Also, some have reported that the activation link is invalid. Anyone have any idea how to resolve this issue or what might be wrong?