Tello Mobile Seems Acceptable but Delay in Dialing is Frustrating

Clark reviewed Tello Mobile and I signed up for the $14 per month plan.

So far so good except for one issue.

When I press the button to make the call it takes 10 to 12 seconds before the phone begins to ring.

Is anyone else experiencing this problem? Could it be because I am testing this on an old Samsung Galaxy S8 phone?

I have seen that issue on my Verizon account. It may be a network/congestion issue.

JUNE 4th: There appears to be an outage with at least one U.S. cellular carrier, with customers unable to place or receive calls. AT&T, T-Mobile, and Verizon customers have been complaining about the issue on social networks, and there are also reports of outages on the Down Detector website.

I have been testing on the Tello $10 plan and have no issues with any delay dialing out. I have tested using WiFi Calling and without.
Samsung Galaxy S9 phone.

I have my 2nd phone on Tello. I checked it and it starts ringing my other phone in about 2 seconds – very little delay.
I have a Moto gPower 2021