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