Same issue here. Was working fine on PHP 5.6 up to 3-10-2017. Then just stopped with error;
2017-10-03 17:30:03 SoapCallFcn::__construct() error: SOAP-ERROR: Parsing WSDL: Couldn't load from ##### : failed to load external entity
We can browse to the WSDL with a browser, but not access with...
Have just come across this on our server;
Commented out as follows
#ssl_ciphers HIGH:!aNULL:!MD5;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
#ssl_prefer_server_ciphers on;
As both were in the pci-compliance.conf file