Memory Limit exhausted. Deleted Plugin - now blanc Super Admin Site

Hello There,
I have just set up my multisite network and started to network activate one plugin after the other. Everything worked fine until I wanted to activate mass email sender.
After activating i received an error that the memory limit is being exhausted. So I deleted the mass email sender plugin via FTP and now the error message isn't displayed anymore but my network admin page is completely blank.
Can you tell me what to do?
Thanks alot in advance

**EDIT #1:
before deleting the plugin, I tried to set the WP_MEMORY_LIMIT to 256M in my wp-config.php but that didn't help.

**EDIT #2:
Ok I have figured it out. I had to add an additional line to my htaccess to increase the memory limit.