Unable to access StoreFront portal when TLS 1.0 is disabled on NetScaler Gateway virtual server.
TLS 1.2 is not supported on StoreFront earlier to StoreFront 3.5.
To resolve this issue upgrade to StoreFront 3.5.
Citrix Blog - Announcing StoreFront 3.5
CTX207162 - Error: "Cannot Complete Your Request" When Connecting to StoreFront