I had same issue -
remote playback was possible only for records taken during night hours, about 4.00pm - 7.00am(November 2018, CET)
First of all try below steps and write if this helped - it works for me!
Go to iVMS-4200 -> Device Management -> Remote Configuration -> Image -> Video & Audio -> set 'Video Quality' to 'lowest'. Default value is normal, set it to lowest, apply and try if this helps.
My Details:
I have DS-7608NI-K2-8P recorder with 4 cameras DS-2CD1141-I(4MP) connected directly to recorder.
4TB Seagate hard drive with continuous recording for all cameras. DNS set to 8.8.8.8. I've tried image compression H.264 and H.264+.
I am using HIK-Connect app on iOS. My internet connection is 20Mbit download and 3Mbit upload.
When at home and using HIK-Connect app with recorder configured as local LAN IP(192.168.0....) everything
works perfectly - I can playback, and watch live view smoothly. Same when using iVMS-4200 on Windows or MacOS.
When accessing system outside my LAN, e.g. at work, I have HIK-Connect app with same recorder configured using HIK-Connect Service connection(using my account and Serial Number).
Live View is also smooth, but I can playback only records taken at night(and about 30 minutes of daylight then it stops).
Also when I got PushNotification about MotionDetection, playback is possible only when it was dark.
I figured out that cameras have 2 streams: main-stream(for day recording), and sub-stream(much lower quality) for night recording.
So remote playback works for me when playing back the sub stream, when it turns to main-stream, there is some problem with HIK-Connect Service.
I don't think this is the upload limit(3MBit) of my internet connection, because live view(in high quality) is always smooth. (
@Callum84 has 20MB up and same problem)
What I did was to decrease the quality of main-stream image and it helped! It didn't decrease file size dramatically, but it works!
You can try changing resolution e.q. to 1080P - this also works.