After trying all other methods I found on Community and other web sites, I finally found the solution that worked for me.
I went into Settings, Connections, Mobile Networks, Network Mode.
Change from Global to LTE / CDMA.
Respond that you want to select the Network manually.
When the list of networks comes up, click on Verizon.
It will then connect in 4G.
At this point, you can change the Network Mode back to Global.