The remote store locate on a Plesk 11.5.30 shows blank page on the customer's login step.
In PHP settings, the memory_limit value for the store website is sufficient.
On Plesk server where remote store is hosted, in /var/www/vhosts/[store-domain].com/logs/error_log the following error is logged:
[Thu May 29 06:19:26 2014] [warn] [client [IP]] mod_fcgid: stderr: PHP Fatal error: Allowed memory size of 52428800 bytes exhausted (tried to allocate 671626 bytes) in /var/www/vhosts/[domain].com/httpdocs/store/includes/nusoap.php on line 6087, referer: https://[store-domain]/store/sign_in.php?redirect_step=domains
Increase memory_limit in /var/www/vhosts/[store-domain].com/httpdocs/store/includes/hspc.php