Exhausted Memory with Ultimate Branding

So I receive the following message, ever since installing the Ultimate Branding plugin:

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 64 bytes) in /www/htdocs/w00b8215/html/subdomains/preview.zughafen.de/agility_wp/wp-includes/meta.php on line 569

I've had this problem before with another site, and I knew that I just had re-adjust the memory limit in wp-config.php, but I've tried every possible amount for example up to 5000M, and it didn't help.

Then I thought, maybe it would help to deactivate the plugin which I most recently installed, and that was Ultimate Branding.
When the plugin is deactivated, my site runs as it should!