After some actions - especially relating to transactional emails - in the frontend (e.g. new customer signup, newsletter signup, forgot password etc.) there's a blank page (e.g. www.domain.com/customer/account/createpost/ oder www.domain.com/newsletter/manage/save/):
If I reload the page manually, everything is fine and the signup also has worked (customer created).
If I disabled System > Configuration > Advanced > System > Mail Sending Settings everything works fine, but no emails of course.
I just activated the log and I got the following exception:
- exception magento /app/code/core/Mage/Core/Model/Email/Template.php:374
FYI: Already tried to setup the cron as described
EDIT: System specs: Cent OS 7, MariaDB on a remote server, Magento CE 188.8.131.52