@Vendex 

Thanks, 

I've made progress, another reset, another loading of the saved config which if anyone is reading does not restore your router password instead favouring the one you had to make up to enter the interface before restoring, so ensure you visit the Admin section and update to the proper password anytime you've done a restore.

Anyhow I tried Tether with the 8 digit dummy PW and it loaded straight up, I then reduced my proper password to 30 characters and still got Login failed contact etc etc etc

I now suspect something between the app and the new ios isn't chatting nicely and breaking the password once it thinks you have too many characters in it, passwords work fine at 32 characters to enter the router with a browser so it's 100% app related.

I also sorted the UK USA thing and it was the search engine that didn't like my gtf settings to stop them data collecting.

UPDATE on FW AX73 v2 UK OTA update from 2 weeks ago roughly.

Your FW is broken with Tether, I've since done 2 things, played with the phone settings which were causing a problem but not on this router, I had the screen closing too fast in my settings, once I adjusted that out for a longer period my other TP-L  AX lower spec router which I brought out to test hooked straight into tether no problem.

I then tried again on the AX73 and no dice same error again.

This means it's not ios26 causing it so it can only be the FW update which is the one not on the support page yet.

I will continue to play so if no update follows it's still broken.

Nope no dice, I've tried everything I know to get it to connect to the app and it's just login failed each time

FW is 

1.2.1 Build 20250717 rel.40826(4555)

Plus I haven't found the switch for turning off the VPN either.

Could you publish the new FW on the support page so I can see if I got a corrupted download ota or not

As said it all works fine on another model that hasn't had an update since late last year, too much of a coincidence if that works under the same circumstances the other doesn't.

It seems to be a trunking problem as I can login if I use an 8 digit password.

Ok further testing reveals this.

Tether works as intended up to a 25 digit password, when I attempted 30 it failed again and 32 lets not even go there eh.

So my conclusion based on another of your routers that hasn't had an update for a while that logs on fine with 32 characters it can only be something having a conflict with it's own new FW in the AX73 as if it was ios or my settings neither router would work.

There's a workaround if anyone else is having this issue set a 25 character password max until they sort this out for us.

I'll just do without it for the time being and it would be nice if someone from the support team responded as this has dropped to page 4 & 5 each day without so much of a whisper.

And will you please publish the FW file on the router support page, it's neither on the UK or Global page yet.