Ok thats custom domains afaik

Sources/MuxPlayerSwift/Fairplay/ContentKeySessionDelegate.swift

@@ -110,6 +110,17 @@ class ContentKeySessionDelegate : NSObject, AVContentKeySessionDelegate {
         }
     }
 
+    func makeLicenseUrl(playbackOptions: PlaybackOptions) -> String {
+        let customDomainWithDefault = playbackOptions.customDomain ?? "mux.com"
+        let licenseDomain = "license.\(customDomainWithDefault)"
+
+        if("staging.mux.com" == customDomainWithDefault) {
+            return "license.gcp-us-west1-vos1.staging.mux.com"
+        } else {
+            return licenseDomain
+        }
+    }
+
     func handleContentKeyRequest(_ session: AVContentKeySession, request: AVContentKeyRequest) {
         print("<><>handleContentKeyRequest: Called")
         // for hls, "the identifier must be an NSURL that matches a key URI in the Media Playlist." from the docs
@@ -135,8 +146,7 @@ class ContentKeySessionDelegate : NSObject, AVContentKeySessionDelegate {
             return
         }
 
-        let customDomainWithDefault = playbackOptions.customDomain ?? "mux.com"
-        let licenseDomain = "license.\(customDomainWithDefault)"
+        let muxLicenseDomain = makeLicenseUrl(playbackOptions: playbackOptions)
 
         // get app cert
         var applicationCertificate: Data?
@@ -177,7 +187,7 @@ class ContentKeySessionDelegate : NSObject, AVContentKeySessionDelegate {
             }
             // step: exchange SPC for CKC using KeyRequest w/completion handler (request wants to know if failed)
             // todo - drmToken from Asset
-            handleSpcObtainedFromCDM(spcData: spcData, playbackID: playbackID, drmToken: drmOptions.drmToken, domain: licenseDomain, request: request)
+            handleSpcObtainedFromCDM(spcData: spcData, playbackID: playbackID, drmToken: drmOptions.drmToken, domain: muxLicenseDomain, request: request)
         }
     }