Is there any update on this? I spoke with Spectrum and changing my router is NOT an option. The router I have is the one that they are currently sending out to all customers. Is there no firmware update that tp-link can push to these extenders? I just spent a LOT on this new extender with the expectation that it would be fairly generic with most of the big internet providers. I can't return it at this point so I really need tp-link to step up. 

@SBBradford 

At this point we are waiting on a solution.  We are told it will be soon but no ETA.  If you have just cable service is it possible to purchase your own router, and even modem.  The modem will have to be on Specturm's compatiblity list and be compatible with your service type.  Their list should be able to tell you will approved modems work with which speed packages.  The router can be any router as long as its ethernet ports will support your speed package.  For instance if you have a 300 Mbps then you will want 10/100/1000 or Gigabit ethernet on the router.  

This will help advoid costly rental fees that most ISPs charge.  

Once we do have a fix we will let everyone know.  

I sincerely wish that people would stop suggesting "buy your own equipment.

1 - purchasing your own equipment won't guarantee that things will work either

2 - buying MORE equipment is EXPENSIVE - maybe that won't break everyone's bank but I - and many others - don't have the money to drop on our own equipment or we would have already done so before coming to a forum about this issue, and

3 - not EVERY ISP charges for their equipment these days! 

I'm just hoping tp-link will jump through the necessary hoops to make this work. Can't begin to express how frustrating this has been after working on it for several days trying to troubleshoot the issue and then finding out my time was completely wasted. Wherever these are being sold, there needs to be an included statement that they do not currently work with the widely distributed Spectrum equipment so people will buy other models. Had I known, I would have purchased different equipment. It frankly is completely worthless to me - and it was NOT cheap.

Thanks for your reply and I hope that tp-link will quickly come up with a solution. In the meantime, warn people, please! I'm sure it's complicated. 

@Carl This sure is NOT a TP-Link issue.  I have the exact symptoms with my Netgear E-7000 range extender.  Worked fine with old weak Spectrum router 

I have tried everything with no result.  Since it has been 8 months since you defined this flaw, and it still exists on Spectrum’s latest router I give up and will shell out for a better router, one with external antennas, also.  Thank you for your definitive analysis of the problem.

Tony

@SBBradford 

You are correct some ISPs do not charge for equipment, but that is typically only when you have a package deal with them including phone service.  Most ISPs still do charge.  Since we can't fix the issue as it is with the ISPs provided equipment the suggestion to use your own equipment is a valid option.  Yes there is a cost involved but it would solve the issue at hand.  Now if you do not want to go through the hassle of switching ISPs or buying your own router and or modem there is another option, Powerline.  

Powerline adapters sold in kits connect one unit to your router via ethernet and then sends a signal to a 2nd unit through your home's powerlines.  We have wired and wireless versions.  I would recommend the TL-WPA7510 Kit.  Its remote unit is wireless with both 2.4 and 5ghz band and can be cloned to use the same SSID as your router.  This device retails for around $60.  As it uses ethernet and powerline the communication issue you have with the Range Extender wouldn't be a problem.  There are a few things to know about powerline, such as that all adapters have to be connected to circuits in the same electrical panel,  so if your home has a main panel and a sub-panel adapters on the sub-panel would not communicate with adapters on the main panel.  

If anyone is interested I have a spectrum router and re450 extender.  I worked with customer service half way around the world.  They solved the problem of no internet connection by changing setting in the re450 extender software and also 2 setting the the specturm router.  I can help someone if they need it.

@behrens I am most interested.  Please help!  How did you get the extender  working with your spectrum router?

@behrensr can't you just share on here what they did?

@Carl I don't have any more money to spend on this. And again no guarantee it would work.