The dreaded exhausted memory allocation….This happens to many people…if you add this in your Google Search:
wordpress Fatal error: Allowed memory size
….you will see what I mean. It’s been a very annoying issue with people. There’s solutions that work and solutions that don’t work, so my best recommendation is to do that search in the WordPress support forums and see what others have done to get it solved. You will more likely have to get into your web host control panel and make some changes.