3 Windows and 1 MAC. One of the Windows machines is a home server which hasn't changed (apart from Windows updates) since the days when it used to work, the others have been upgraded to Win 10. But the 2860 no longer responds with the "Send Command to Client Done" message.

I am having EXACTLY the same issues. All users who access the internet via WiFi are fine, however wired users are having intermittent problems accessing web pages, some web pages are not loading at all.

This all happened since I upgraded to v2860_384_BT firmware.

"somewhat" happy to see someone else is having this problem as I've been swearing at my upgraded Linux Mint PC for a while as I thought IT was causing the issue.

EDIT: Ummmm, anyone know WHERE I can find v3.8.2.3_VT3 to download?

you can get it here http://www.draytek.com/ftp/Vigor2860/Firmware/

but my issues have been resolved with 3.8.4.2BT

I upgraded to this, and whilst I can ping out and connect VPN and DNS is fine, I can get no HTTP or HTTPS traffic out at all on wifi or wired.

This firmware should be pulled ASAP as it causes serious issues.

I have now downgraded to 3.8.2.3 and still not working. I can't access the internet at all. This firmware has basically broken my router.
Edit: reset to default on 3.8.2.3 and after a few attempts my internet is back. I frequently had pages like this when accessing any site, seems like BT don't like the new firmware at all which is ironic. PS I am on Plusnet ADSL (owned by BT).

SERVICE INFORMATION

You have been connected to this page due to one of the following reasons. You must now shut down your internet browser and internet applications before attempting to reconnect. This may clear the issue immediately, if not then please select the appropriate action from list below.
• Your service provider is currently unable to accept your connection request, please wait and reattempt later or contact your service provider for more information.
Or
• You have attempted to access an invalid Service Provider domain, check your user details.
Or
• You are testing your connection using bt_test_user@startup_domain. Please proceed to next step as advised by your Service Provider
Or
• You are testing your connection to your service provider using bt_test_user@domain. where "domain" is your Service Provider domain name. Please proceed to next step as advised by your Service Provider.
Or
• The access circuit to your Service Provider is currently down. Your service should be resumed soon. Please try again later or contact your Service Provider
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I have a 2860 n+, on Zen vdsl (still running over Openreach infrastructure afaik)

Since installing 3.8.4.2BT the router has been stable as a rock, no disconnections on either WAN1 or WAN2 (wifi failover, now working on 5GHz as well as 2.4GHz), no random re-boots, WOL working again.