Unless you set up a cronjob it does not send any email notices in Jomsocial. For example notice for Friend request, Group bulletins, private messages.
My set up is Joomla on XAMPP. If you are using the same, this article may help.
First you need to open C:\xampp\htdocs\JOOMLA\components\com_community\cronjob.php and change the hosting and subfolder.
I found this forum and this screen shot which explains the set up for Jcron.
The screenshot will tell you how to set up a cronjob in Jcron.
My template needed a writable permission and the site was running on XAMPP.
Windows does not have chmod, so I right click the file "mytemplate.php" in explorer in the server and removed the "read only" attribute.
Then going back to Joomla back end > component > JCron > Configuration to run "Enable CRON RUN".
Jcron does the job when someone visit your website or click a menu.
However I thought I need to set up a server side cron job as well.
Going back to Windows server to set up a scheduled task. All programs > Accessories > System tools > scheduled tasks.
I set up every 30min from 7AM for 12 hours everyday.