Getting 401 Unauthorized for replication tasks while the session is still valid on sync gateway

[chayanbhaisare]

I am using Couchbase-Lite-PhoneGap-Plugin version 1.3.1 on Android 6.
I am creating the push/pull replication tasks using coax by passing session id as cookie, initially documents gets properly synced to and from sync gateway. But after few hours even with the valid session replication is not working and I am getting following error in adb logcat:

RemoteRequest: com.couchbase.lite.replicator.RemoteRequestRetry@d422b39: isTransientError, httpResponse: Response{protocol=http/1.1, code=401, message=Unauthorized, url=http://syncgateway-url/testdb/_local/97a82cc76d7a1c80674d7f9bc9625e289764c72d} e: com.couchbase.lite.replicator.RemoteRequestResponseException: Unauthorized
W Sync    : com.couchbase.lite.replicator.ReplicationInternal$11@65e86d7: error getting remote checkpoint
W Sync    : com.couchbase.lite.replicator.RemoteRequestResponseException: Unauthorized

D Listener: authHeader is null
D Listener: Unauthorized -- requestCredentials not given or do not match allowed credentials

This error is part of https://github.com/couchbase/couchbase-lite-java-listener/blob/master/src/main/java/com/couchbase/lite/listener/LiteServlet.java#L56-L68
Part of LiteServlet.java code

 String authHeader = req.getHeader("Authorization");
if (authHeader != null) {
   // some code
}else{
     Log.d(Log.TAG_LISTENER, "authHeader is null");
}

Replication config that I am using:
pullRep = {
    source: {
      headers: {
        Cookie: cookie,
      },
      url: config.site.syncUrl,
    },
    target: config.dbName,
  };

This issue is similar to https://github.com/couchbase/couchbase-lite-android/issues/817