'This page can't be displayed'

[#1]

To check your DNS server use nslookup from a Windows Command prompt.

nslookup bbc.co.uk

On my Mac produces :

nslookup bbc.co.uk
Server: 192.168.0.1
Address: 192.168.0.1#53

Non-authoritative answer:
Name: bbc.co.uk
Address: 212.58.244.22
Name: bbc.co.uk
Address: 212.58.244.23
Name: bbc.co.uk
Address: 212.58.246.79
Name: bbc.co.uk
Address: 212.58.246.78

By default the search order for DNS on Windows is:

1. Host File
2. Local DNS Cache
3. Preferred DNS
4. Secondary DNS
5. Tertiary (if you have one)

When an address can’t be resolved by either step 1 or 2 then the DNS server you (or DHCP) assigned for that interface at step 3 with be tried. So when you have two interfaces, like in your case, of WiFi or LAN then you would need to either manually override both of these settings as mentioned in a previous post or ideally change your router’s settings to give you the DNS servers of choice.

When the router is changed the DNS servers configured there are used for all connections that use the router regardless of type and saves you a lot of faffing around and is IMO the best option.

[#2]

Alternatively, get yourself a copy of Linux

jeremy@hector ~ $ host bbc.co.uk

bbc.co.uk has address 212.58.244.22
bbc.co.uk has address 212.58.244.23
bbc.co.uk has address 212.58.246.79
bbc.co.uk has address 212.58.246.78
bbc.co.uk mail is handled by 20 cluster1a.eu.messagelabs.com.
bbc.co.uk mail is handled by 10 cluster1.eu.messagelabs.com.

[#3]

What was the point of that post? Sorry but neither your response or the output serves any purpose as their is no resolver information provided and changing the OS will have no effect if the router is the issue.

[#4]

Actually if your router contains proper DNS resolvers then its highly unlikely that anything is broken, if it works "nearly all the time".

Since its mostly wifi usage, does it only fail on wifi and do you suffer from a poor signal strength?

[#5]

I would use ipconfig /all from a CMD prompt to check your DNS settings.  Or if you changed the DNS settings via your Network Adaptor settings go back and look.  Each network adaptor has its own settings and, potentially, its own DNS server so WiFi or wired can make a difference.  But the default setting is to refer to the router in which case it makes no difference.

I never trust security software not to malfunction.so you might try temporarily uninstalling AVG to see if that makes any difference.

[#6]

Managed to run iconfig, results below. Laptop ethernet connected to router, but wifi on.

Microsoft Windows [Version 10.0.14393]

(c) 2016 Microsoft Corporation. All rights reserved.

C:\Users\XXX>ipconfig /all

Windows IP Configuration

   Host Name . . . . . . . . . . . . : this device

   Primary Dns Suffix  . . . . . . . :

   Node Type . . . . . . . . . . . . : Hybrid

   IP Routing Enabled. . . . . . . . : No

   WINS Proxy Enabled. . . . . . . . : No

   DNS Suffix Search List. . . . . . : lan

Wireless LAN adapter WiFi:

   Media State . . . . . . . . . . . : Media disconnected

   Connection-specific DNS Suffix  . : lan

   Description . . . . . . . . . . . : Qualcomm Atheros AR9485 802.11b|g|n WiFi Adapter

   Physical Address. . . . . . . . . : A4-DB-30-2E-71-1D

   DHCP Enabled. . . . . . . . . . . : Yes

   Autoconfiguration Enabled . . . . : Yes

Wireless LAN adapter Local Area Connection* 11:

   Media State . . . . . . . . . . . : Media disconnected

   Connection-specific DNS Suffix  . :

   Description . . . . . . . . . . . : Microsoft Wi-Fi Direct Virtual Adapter

   Physical Address. . . . . . . . . : 16-DB-30-2E-71-1D

   DHCP Enabled. . . . . . . . . . . : Yes

   Autoconfiguration Enabled . . . . : Yes

Ethernet adapter Ethernet:

   Connection-specific DNS Suffix  . : lan

   Description . . . . . . . . . . . : Realtek PCIe FE Family Controller

   Physical Address. . . . . . . . . : A0-48-1C-23-75-F5

   DHCP Enabled. . . . . . . . . . . : Yes

   Autoconfiguration Enabled . . . . : Yes

   Link-local IPv6 Address . . . . . : fe80::4058:4e7e:9609:23b8%14(Preferred)

   IPv4 Address. . . . . . . . . . . : 192.168.1.70(Preferred)

   Subnet Mask . . . . . . . . . . . : 255.255.255.0

   Lease Obtained. . . . . . . . . . : 22 November 2016 19:51:13

   Lease Expires . . . . . . . . . . : 24 November 2016 19:37:29

   Default Gateway . . . . . . . . . : 192.168.1.254

   DHCP Server . . . . . . . . . . . : 192.168.1.254

   DHCPv6 IAID . . . . . . . . . . . : 211830812

   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-19-95-42-18-A0-48-1C-23-75-F5

   DNS Servers . . . . . . . . . . . : 8.8.8.8

   NetBIOS over Tcpip. . . . . . . . : Enabled

Tunnel adapter isatap.lan:

   Media State . . . . . . . . . . . : Media disconnected

   Connection-specific DNS Suffix  . : lan

   Description . . . . . . . . . . . : Microsoft ISATAP Adapter

   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0

   DHCP Enabled. . . . . . . . . . . : No

   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Teredo Tunneling Pseudo-Interface:

   Connection-specific DNS Suffix  . :

   Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface

   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0

   DHCP Enabled. . . . . . . . . . . : No

   Autoconfiguration Enabled . . . . : Yes

   IPv6 Address. . . . . . . . . . . : 2001:0:5ef5:79fd:109b:1b3a:2ea2:7a1b(Preferred)

   Link-local IPv6 Address . . . . . : fe80::109b:1b3a:2ea2:7a1b%9(Preferred)

   Default Gateway . . . . . . . . . : ::

   DHCPv6 IAID . . . . . . . . . . . : 150994944

   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-19-95-42-18-A0-48-1C-23-75-F5

   NetBIOS over Tcpip. . . . . . . . : Disabled

C:\Users\XXX>

I have no idea what most of this means, or if any of it should be redacted for security purposes (advice welcomed), but it does appear that the ethernet connection is using google dns 8.8.8.8, as set in response to @Anonymous's response. With the laptop physically connected to the router via ethernet and with wifi also on, it is not clear to me which connection is being used. Should I try to repeat the ipconfig report with wifi off, or with wifi on and ethernet disconnected?

[#7]

So this says that you did not follow  @Anonymous's suggestion right at the start of this topic for your wired (Ethernet) adaptor.  Or if you did then you changed it back again.  The DHCP server for this connection is still pointing at your router.  

There is no explicit DHCP server given for your wireless connection.  I'm not sure if that means the same is true for your WiFi or if it's just a consequence of you not having a wireless connection at the time.

[#8]

@ReedRichards thanks for your quick response. Subsequent to my initial attempt to change the settings I reset them as per your advice in an earlier response. What is the significance of the DNS servers 8.8.8.8 entry. 

The laptop may be prioritising ethernet over wifi, so I'll see if disconnecting either/both makes any difference now that I have an idea of what to look for.

[#9]

From that output I see that the LAN is taking priority over your WiFi as it’s reported as disconnected, implying that the act of connecting a LAN cable auto disables the WiFi, which makes sense to me.

In post number 2 I asked that you locate and double click the …(TCP/IPv4) entry from the LAN properties, I would also suggest that you go back to this properties dialog and disable the TCP/IPv6 option as this only gets in the way and as you are not using it and I suspect do not even have support for it on your connection it is best left disabled. Do this for both the WiFi and Lan Adapters, and while you’re at it remember to set the DNS on the WiFi adapter as well.

Just to clarify what @ReedRichards is saying, I did ask you to only change the DNS servers in the connections properties and nothing else.

As regards for redacting information you may want to remove any MAC addresses and execute a search and replace on your PC’s username, as the XXX in the C:\Users\XXX> wasn’t enough.

Once you’ve made the changes to the adapters re-run ipconfig and post the output please, and see what difference this makes to the error you have been getting regarding “this page can’t be displayed”.

[#10]

@maranello, I never intentionally advised you against setting the DNS server to the Google one ( 8.8.8.8 ).  My own LAN settings have 8.8.8.8 as the first choice and my (Netgear) router as the second choice so I only get to the Plusnet DNS servers if the Google one fails to respond.  

[#11]

Firstly, thanks to everyone for all your helpful advice. I now have a better understanding of what to look for and change, and how to go about it. I've just not had the time to act on it due to other demands on my time, but hopefully I'll be able to have a go over the weekend.

@ReedRichards, to clarify, it wasn't my intention to imply that your advice contradicted that of @Anonymous. In fact, your suggestion is similar to one I had already seen on the Windows help site. But I think it is clear from the ipconfig output that having done the settings reset after following @Anonymous's advice those changes have been undone. 

I'll update this thread when I have made the changes to both the LAN and Wifi connections, and post the ipconfig report. I have also found further advice to the effect that having made the changes it is advisable to flush the dns cache afterwards using the command ipconfig /flushdns. Here's hoping that I can report back with a positive outcome.

[#12]

I went to visit a computer and router today with this sort of issue. Pages sometimes failed to load or some images failed to load on a web page with a lot of pictures.  Changing the adaptor settings to make the primary DNS 8.8.8.8 appeared to fix the problem.  

[#13]

Was it a Technicolor router? Was the router serving up 198.18.1.x IP addresses? If so, why did you not fix the router?

[#14]

Yes, it was a Technicolor 582n router.

I think the IP addresses were 192.168.1.x (I presume that's what you meant).

@ejs you posted links to two threads.  The first ran to 12 pages and I wasn't even sure it contained a fix.  The second is two pages long and does not contain a fix.  If there is a fix, @ejs, it would be helpful to post what it is here.  And I hoped that Plusnet would roll it out in due course anyway.     

Moderator's note by Mike (Mav): Full quote of preceding post removed as per Forum rules.

[#15]

I've searched high and low for the router fix referred to by @ejs.  I think it might be to telnet into the router and issue the commands:

dns server config WANDownSpoofing = disabled
dns server debug spoof clear
dns server debug spoof list
saveall
exit