Change of password and Email activation problems

It seems that since I updated CB, my users are having some trouble. Before, everything was working fine. Now, when they change their password they get this:

"I have requested and received a new password, but even after using the new password to log in, I get the following error messages.

"You can't access the private section of this site."
"Please log in or sign up to view or modify your profile."

When I hit the "Sign In with Facebook" button, I get:

"You can't access the private section of this site."
"You have successfully logged in."

-- Suggestions?

Also, a lot of the time when people sign up, they are not receiving their email activation... and when I activate them manually, they have trouble logging in.

That's a Joomla access error. What did you upgrade from? If you migrated from CB 1.x then edit all your Joomla menu items that point to CB and fix their menutype as they will be invalid. If already on an existing CB 2.x then ensure you've a public and published Joomla menu item to CBs profile page.

I had Joomla 3.5 and CB 2.x. I assume, then, that your second solution is likely the correct one. How, exactly, do I go about fixing that? *sheepish* I'm not entirely sure how to do it.

Create a Joomla menu item to CBs profile page if one doesn't exist already then ensure it's public and published. All of these menu items shouldn't created on install and be under the "Community Builder" menutype though.