@David-TP 

No, the RE505x was never hardwired to the AX20.

However, your question led me to try something more and I found that the network interference disappears if I remove the cable linking the RE505X to a mini computer.

This was the reason for which I bought the RE505X, i.e. to supply a network connection to that mini computer which doesn’t have a Wi-Fi card and is not located near an Ethernet jack.

But I have now also done another test: I hardwired the RE505X to another device (a normal laptop, with its Wi-Fi disabled) and the interference came back.

So it’s clear that the RE505X gets messed up as soon as anything is plugged into its RJ45.

I guess I’ll have to return the RE505X to the store.

  @David-TP 

The RE505X’s hardware version is 1.0.

Yes, the AX20 is connected only to a wired router, which in turn is connected to the modem. That is called a cascade setup. I have always used this arrangement, ever since I got my first Wi-Fi router in the late 1990s. I cannot connect the routers in any other manner, because of physical location constraints.

  @RedRobin 

Hi,

I have a TL-WA850RE(EN) Ver:7.0 range extender and when I connect it I can no longer navigate with the router's main network (always TP-LINK). Everything is configured correctly, in fact if I disconnect the range extender I can navigate perfectly on the main network. If the range extender is active I can only browse with the extended network. 

I think I should do a firmware upgrade but the problem is that in the download page I can see the firmware with EU tag, because it redirects me to the Italian page but my range extender as the tag EN (even if I bought here in Italy) TL-WA850RE(EN) Ver:7.0.

This from the download page

How can I download the EN version ? Or the EU version would be fine anyway ?

Thank you.

  @David-TP 

I ran into this problem having had the Model: TL-WA854RE  Extender (Hardware Version: V4, Firmware Version: 1.0.12) in and working fine for a couple of months. I also have a number of Gb TP-Link switches (5 and 8 port) in my Ethernet which connect to a TP-Link Archer VR2800 router.

A week ago I found that whenever I woke my PC up from sleep it would not connect properly to the Internet. In fact while it thought it was connected to the routerr ok, even that wasn't so as it was a struggle to connect to other devices on the LAN. I found that I could fix it by power cycling the 5 port switch on my desk, until the next sleep/waking when I would have to power cycle again.

I then found my Laptop on WiFi would not connect properly either and that I did not find a fix for, but occasionally it start working and continue till I put that to sleep. My mobile phone also started playing up.

Thinking it might be the TP-Link Router, I replaced it with the ISP provided one and the problems continued.

I got in touch with Talktalk who could see a problem and unbenown to me they capped my line at 2Mbs. That sent me down a rabbit hole and after 2 engineer visits it got resolved and the router plugged into the master socket with nothing on its LAN apart from a laptop showed all was well and I had my speed back. So I then started adding elements of my network and found that it was the 2.4GHz WiFi that was the problem. I have around 15 devices on that band!

One of the first I looked at was the Extender and connecting to it with a browser and its IP address noted that I could fix its IP address (as most static things on my LAN are), but also that it had what looked like its own DHCP Server which was set to Auto with an IP range of 100-199. This is part of the range in which I have my static devices (eg Televisions, Desktop PC etc) set with their manually assigned IPs, so that got me wondering if there was a clash going on. So, along with giving it a manual IP address of its own (within my range) turned the DHCP Server to Off.

Now 24 hours later I can report that I have had no further problems.

I will keep monitoring it and come back if the problems return.

  @David-TP I have the same issue with a WA860RE_V6 connected to a Fritz!Box 7510. When the repeater is connected, the Fritzbox seems to still be online but most servers can't be reached. Other divices can connect to the fritzbox but not to the internet.

 The repeater is on TL-WA860RE(EU)_V6_1.0.12 Build 221109. Do you think the issue is with the firmware or should I look somewhere else ? I see that this repeater hardware revision is listed on the first post, however, the file linked seems to be for the WA850-REV7. Is this a mistake or these two models can run the same firmware ?

  @Exandrek 

Have you tried logging onto the device (type its IP into a browser) to see if you have a similar DHCP setting?

I didn't update the firmware. It seems that changing the internal settings to disable the DHCP server did the trick. Or it could have been giving it the fixed IP address, but that's a lot less likely.

I said in my previous post that it had gone a day with no problems. It's now been a few weeks and my network has been solid. I have 2 x TP-Link range extenders now.

  @Graham307 The issue seemed indeed to be related to DHCP, the range extender is using the same subnet as the main router and it apparently gets the same ip (192.168.x.1). The issue as far as I could see was that another device would also recieve the ip 192.168.x.1 which probably messed up the NAT explaining the issue getting responses from remote servers (wild guess from what I remember from an old networking class). Applying the patch this morning (Thank you @David-TP for the quick reply) seemed to have solved the issue but if it comes back, I will either change the DHCP settings or configure a different subnet for the range extender. I'll try to remember to give an update in a few days if everything is still stable.