I can not log in to 192.168.0.1 or 192.168.15.1. Tech support is not available any more suggestions?

Reset for most routers with a reset button on the rear panel

Write down configuration information such as IP addresses, security keys, opened ports and services, etc. that you modified. (The default username is admin and the password is either password or 1234. Try these before resetting the router.)

Press the reset button on the back until the test light blinks. This takes about 10 seconds. (To avoid accidental resets, the small button is recessed. Use a pen or paperclip to access it.)
Release the button.
Wait for the router to reboot.
Log in with the default password.
If the router was not cleared, try these additional steps AFTER the router has finished rebooting.

Unplug the router's power.
Press and hold the reset button. While the button is held down, reconnect router's power.
Continue to hold the reset button for 20 seconds after reconnecting the power.
Wait for the router to reboot.
Log in with the default password.