jr2009 on "[Plugin: WP e-Commerce] Emails not sending"

I'm using WP e-Commerce v3.8.11.1 & WP E-Commerce shop styling v1.9.2. Emails were sending fine. But after several test checkouts (using manual/test gateway) to check the look for the emails, the emails stopped sending to customer and I don't receive the admin transaction reports either.

Tried to clear purchase logs from database, but it still doesn't send out. Anyone knows why??

http://wordpress.org/extend/plugins/wp-e-commerce/