fatal error - out of memory

getting a fatal error - out of memory

Fatal error: Out of memory (allocated 775159808) (tried to allocate 72 bytes) in /home/perfum29/public_html/wp-includes/taxonomy.php on line 1391

whenever some one tries to login in on our site - http://www.perfumeuae.com from this link -

https://perfumeuae.com/my-account/

please help