New Modem for Verizon DSL cannot access GUI

Kala_70

Bought a GT784WN modem/router to replace an old GT704WGB.

All drivers for Ethernet on my computer are properly installed, DHCP/Dynamic IP is enabled.

When trying to access the GUI to the new modem "192.168.0.1" with the DSL/Phone cable unplugged, it operates as it should.
I can modify settings, set passwords, etc.

However, whenever the DSL/Phone cable is plugged into the modem, I receive a "Cannot connect to page" error in both IE and Chrome.
This happens even if I restart the modem, and I have to unplug the DSL/Phone line to see the GUI display again, without error.

The Quick Setup guide for the new modem asks is DHCP/Dynamic IP is enabled, which it is, no further troubleshooting info.

So far I have tried:
-setting modem IP to 192.168.1.1 (IP of my old modem)
-connecting cables in different order.
-Resetting modem to factory defaults (twice) (still receive "Cannot connect to page" error when DSL/Phone is plugged in)
-No there is not a DSL filter on the modem's DSL/Phone cable.
-Searched Gewgelleleolol for similar problems, nothing turned up (don't be discouraged to try however)

I am thinking faulty modem.
or lemon user. (OP)
~your thoughts.
Thanks.

dslr595148

Do you have a RJ-45 WAN port router connected to this modem OR is that modem combo the only router that you have that is part of your network?

If you do not know the answer to my question, then list everything that is connected by wire to this modem combo - besides common sence things.

By common sence things, I mean a power wire and a phone wire.

^^^