Hosting Memory Limit

Hey guys,
I tried to increase the memory limit of my WordPress site and added the following code to the wp-config.php:

define( 'WP_MEMORY_LIMIT', '1024M' );

define( 'WP_MAX_MEMORY_LIMIT', '1024M );

But that does not seem to change anything. I use the plugin Mailster and it still tells me that my memory limit is at 1MB. I tried different memory sizes, does not change anything. I also made sure to add the code before the stop editing part.
Any ideas?
Best
Johannes