@Shubham When a call is made across different networks, the other network has to accept the call and provide termination facility, which it may provide on receipt of termination charges only. Jio must be ready to pay the interconnection/ termination charges during testing period when it does not get any money from users. During the trial period of Jio Volte calls also, other service providers were not terminating the calls for the same reason.
Jio to Jio (VOIP and VOLTE) calls however, may be through right now.