I had been running my V 166 on my line for a couple of months, it had been a solid connection for over 4 years. The 166 sync’d at the same speed my V130 did. My line went unserviceable the other day, so after rectification the line went into its normal 10 day training as per a new line. Sadly the V166 cannot hold the line sync during this period, the line comes up gets a good sync, going up and down a few k each time. It only stays sync’d for about 5 secs before dropping the line. This just keeps going on constantly, I left it for two hours and it never stabilised. I then put my V130 back in place of the V166 and in sync’d straight away and has remained stable at the expected sync rate.
Put simply the V166 has a whole raft of problems and should never have been released. Just for clarity each device has the latest BT firmware on it.

Have you checked that the settings are correct?

Have tried resetting to factory defaults and then starting again?

Have you contacted Draytek support?

Factory defaults are the correct settings. Email sent to draytek but no response yet.

mike.smith wrote:
Factory defaults are the correct settings. Email sent to draytek but no response yet.

I'm sorry, but how's that?

Would you post screenshots of your WAN page (ensure you remove the username and password)

If you're getting sync, but the router isn't holding onto the line (drops the connection soon after), then there's a problem with your settings.

So, check your username, password, MTU value, TAG values etc. Here's a guide for BT/Plusnet users:

https://www.draytek.co.uk/support/guides/vigor-2860-vdsl-setup?return=8569080

thanks but sorry but your comments are irrelevant in this case as its being used as a modem in bridge mode. The only relevant setting is the vdsl tag of 101 which is factory default on the BT firmware. The login comes from the attached router, a 2962, which remains unchanged. The modem does not require any login info to sync the line.
So for me it’s either a faulty device or another fault in the firmware.
Hope this clarifies for all

Well, I'm not a mind reader, you know.

So, you've not tried in the router mode then.