Hikvision DVR streaming delay

In my hotel I have two DVR system, each one have 16 cams connected to it, so a total of 32 cams. Everything seems fine when I watch locally, but when I stream it over the internet on my ipad (with ivm-4500), thing started to go wrong.

That is the delay, the whole feeds got delayed between 60-80 seconds from the actual time. And also each camera has their own delay time.

Can anyone please tell me the reason? Is it because of the upload speed of my network, or some configuration errors? I corrected the time and timezone, but the problem still occur.

Please, this is very important to me.

Slow network/internet connection/ipad wifi/whatever.

Make sure you are using the substream on iVMS-4500, and if needed, lower the bitrate on the substreams.