AOS stops using internet proxy and is unable to post credit card transactions

We have an issue with our AX 2012R3 CU8 installation. We are currently setup to process credit cards through MS payment services. Typically our AOSes will use the operating system’s proxy configuration and route all credit card transactions through our proxy server. There are times when an AOS will “forget” its proxy configuration and start trying to go direct to the internet instead of useing our proxy server. This results in failures when trying to process credit cards, and the only way to fix this is to restart the AOS service on the affected server. Has anyone seen this behavior before? Can anyone provide guidance for the best way to set proxy congifuration on our AOS servers?