Hey.
I was in the same predicament, as I had inherited an RT-AC68R, and the prior posessor did not know the new admin/password combo. I dug and dug through mounds of possible fixes to no avail; even the 30-30-30 did nothing.
I then stumbled upon an answer that seemed irrelative, but worth a shot at this point. The following is what I did :
- Unplug your RT-AC68R Router
- Press and HOLD the WPS Button on the side
- While holding the WPS button, re-insert the power cord
- Hold for approx. 10 seconds (or until the power LED begins to blink quickly)
- Release the WPS button and wait for the Router to do a full Powercycle
After this very simple, but still strangely different method of "factory reset" I witnessed a miracle after 3 months of struggling. I re-accessed router.asus.com or 192.168.1.1, and it allowed me to complete the setup of the router. I did this again just the other day, because I still couldn't believe it, but so far, it has worked every time for the RT-AC68R.
Good Luck! Hope it helps.