Maybe I missed to delete code for groups (I tested profiles). Thank you for notice, I will delete in groups also

Hello, I think I have the last versión.

Greetings.

Because you are using outdated theme.
http://rehubdocs.wpsoul.com/docs/rehub-theme/theme-install-update-translation/updating-theme-and-bundled-plugins/

пт, 7 сент. 2018 г., 0:58 Sizam Support Help Desk <
sizamtheme+lnYZxGmXjrk1w1VbpBEQ@mail.support-hub.io>:

.

Hello, maybe there is a issue, because I have a problem with another plugin and the support tell me this:

I can see the issue now.

Your theme is not updated for BuddyPress 3.0+. BuddyPress 3.0 removed the legacy forums and a few functions.

The error is

Fatal error: Call to undefined function bp_is_group_forum() in [redacted path]/wp-content/themes/rehub/buddypress/groups/single/index.php on line 48

It happens if a theme is not updated for BuddyPress 3.0+ . To fix it, you will need to edit

/wp-content/themes/rehub/buddypress/groups/single/index.php

and remove the code that looks like

                // Old group forums
                elseif ( bp_is_group_forum()      ) : bp_get_template_part( 'groups/single/forum'        );

That will fix it.