The problem Nancy is your WordPress is using all the available memory and fails, especially when posting the form.
I installed this plugin to see usage and available memory limit
Memory Load and db size Usage
It shows this in admin footer: Memory usage Mem 62.19 of 64M
64M is not enough memory for all the plugins you have
I see these errors in widgets in your dashboard
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 384 bytes) in ///wp-includes/SimplePie/Parser.php on line 73
Please speak to your web host about "increasing the default php memory limit".
Maybe they can increase it to 128M
Let me know if that resolves the problem or not