Who I have the same questioned this topic

I have a new Samsung S9+ and a verizon 4G LTE network extender that won't talk to each other.  The extender is operating and says "in service" on the screen.  On the phone, I've turned off advanced calling and have been within 15 feet of the extender for over 2 hours. When I dial *48 I get the "call cannot be completed" error.  What else should I try?