Failed saving proxy settings

When we attempt to login to Analytics we get a blank screen instead of the AGOL/Portal sign in page, and sometimes we get the blank screen after sign in. We followed the steps in the article below

 

https://support.geocortex.com/optimizerGSCkba?sub-nav=kba&main-nav=optimizer&#!/feedtype=SINGLE_ARTICLE_DETAIL&criteria=BESTANSWERS&id=kA3600000004NjmCAE

 

But when we tried to configure Geocortex Analytics ArcGIS Identity Setup using proxy we received the below error message "Failed saving proxy settings"

 

 

 

Analytics v1.2