Help with A850 HD box please

Hi everyone, just got the HD box and must say the quality is brilliant. I'm having problems only on the HD channels with major freezing on them - making them unwatchable. Also I can't rescan the channels - nothing comes up when I do. Can anyone help? Thanks in Advance

btw I have the modded box

Little unclear Payal, "quality is brilliant", after scan "nothing comes up"
Does this mean you now have no channels.
Connection between box and router, best if wired.
Scan direct from wallsocket no splitter.
Swap splitter for another if you have one, if using ethernet cable change.
Channels search type should be "Network"

Sorry for not being clear.
I only have problems on the HD channels. All other channels are working fine and the quality on normal channels is "brilliant".

I did a scan from the wall without any splitters and Channels search type was "Network" and the chose NTL (I tried the others aswell) "nothing came up" in other words no channels were registered in the scan. I think this has to do with one of it's settings. It scans on QAM 64 - I think it needs to scan on QAM 256 not sure on this (can someone check please). Also I don't know how to change the setting on this. How do I scan QAM 256?
Connection between box and router is Wired, I don't think this is the problem as non HD channels are fine.

I hope this is abit more clearer. Need any more info?

Box scans both 64 & 256 QAM, most channels are 265 QAM with very few 64 QAM.
The reason the box don't pick them up when scanning is because they are already there although freezing, if you were to delete them they would be pick up.
Try rebooting router/hub/box
Go to a HD Ch that's freezing, menu/manual search/will show Qam in Mod it can also be change if needed.
Is the firmware up-to-date

Sorry of the delay. I disconnected HD box from router and plunged directly in modem to rule out router, did a power cycle of both modem and hd box. Checked firmware is up-to-date. It still doesn't scan (I left it to scan for a whole hour). I think I will have to post some pictures so you can see if I'm doing it correctly. I found the QAM mod it but don't know what settings to use. Thanks for the help so far. I'll post bk with pics

Check your provider from VM sub box, Settings-Tech Stuff-NetID, what does it show.
Is the box being scanned on Network
Using a HDMI cable to your HD TV is best.
https://youtu.be/xpdNBi5OEpo

Thanks for the link. I did a factory reset and followed the steps. I suspect the supplier used a different Net ID as he didn't do a scan from my feed. All is working well now and a big THANK YOU for all your help. I feel a little stupid now as I should have found out from the supplier how to do this when he installed it. I owe you some beers - thanks a lot.

supplier only sells a fta box,which is then updated by firmware,however there is more to scanning in channels now and not like pre n3 boxes,new boxes never assume you are on certain provider or net id as things change and can only be confirmed with info from providers box,have you made a note of that info for the next time when needed? we were all in this stage at once thanks to utube life is getting easier lol