Can't activate esim on different carriers

Question

Hello, I have Iphone got it more than a Year ago, no outstanding balance or anything, have been loyal to Verizon for decades, wanted to activate esim on different carrier, but sim not supported contact carrier trying for several days without luck to get the info what's happened.
At last got here, hope here is someone could help me thanks

Albrean_VZ · Accepted Answer

Update: Devices were purchased on a prepaid account.  After looking up the devices IMEI, it was determined that device was not eligible for a sim unlock.