ReadyCLOUD not uploading pictures from Iphone

Like to provide some data and details.

I have a Samsung S7 that works flawlessly, issue is only with iOS devices.

Using a iPhone 5 and iPhone 7 the app provides two different behaviors. 

Please note both iPhone were connected via Wifi ONLY.

iPhone 5 will error out a message "Internal Server Error (500)" when the upload hangs.

iPhone 7 will just hang and show NO errors.

I was able to do a port sniff on the traffic towards the NAS to determine the following.

The Samsung S7 seems to be using TCP to do transfer when on WiFi and uses HTTP when on LTE.

The iOS devices seems to use an alternatives method through the internet via Amazon Data Center (guessing due to NSLOOKUP of IP Addresses)

Non-authoritative answer:
8.145.86.54.in-addr.arpa	name = ec2-54-86-145-8.compute-1.amazonaws.com

After mulitple testing, the following list of IP addresses was compiled.

54.177.220.148
54.176.138.14
13.56.2.59
34.232.29.118
54.86.145.8 <-- ALWAYS HANGS on this server

As shown in the screen capture below, the last server disconnect packet is always stuck on 54.86.145.8. 

Both iPhone 5 and iPhone 7 behaves the same. 

The first question to the engineer for the iOS app is why isn't the iOS devices using local IP addresses to reach the NAS when on WiFi?

IF there is restrictions becuase of iOS coding, there need to be an investigation towards why that last server is causing issues to prevent uploading. 

As it seem there are multiple servers to do load balancing for traffic purposes, there could be an issue to one particular server that need to be addressed (assume by Amazon Data Center folks).

Please follow up on the data above and please fix ASAP. 

Thanks