Hello Jomsocial
The new user when registering and complete the registration when click on the activation link and try to logini.It show that you are logged in after that the popup show and ask you for a lo-gin again.
See Screenshot.

Hi.

Make sure that you have latest version of JomSocial -> 3.2.1.1
If not, upgrade to the latest one:

0. Make a safe copy of your whole system (files and database)
1. Browse to Backend -> Extensions -> Extension Manager -> Manage
2. Search all extensions using filter "com"
3. Uninstall all JomSocial related extensions
4. Search all extensions using filter "jom"
5. Uninstall all JomSocial related extensions
6. Download latest JomSocial package from here: www.jomsocial.com/component/digistore/licenses
7. Unzip it
8. Install com_community package via Joomla! installer
9. Follow installation steps
10. Install iJoomla installer for future version check and upgrade.

After that you'll need to do a menu fix also:

When you upgrading JomSocial menu items in JomSocial toolbar lost "connection" with component. Joomla! mark them as disabled and with notice: "Component 'com_community' does not exist". In order to fix it please follow this instruction:

- click on menu item in JomSocial menu in order to edit it
- when in edit mode don't change anything
- save
- menu item should be fixed
- do it for every JomSocial related menu items (if needed) in all other menus

This should solve that issue.