Who I have the same questioned this topic

Samsung Galaxy S7 Edge. Restarted it many times & no help.

On 8-12-21, I call my home Cox landline, as I do virtually every day and instead of it ringing, I get a Verizon wireless message saying the call cannot be completed as dialed please check the number and try again.

Or it says: “This is Verizon Wireless. The called party is temporarily unavailable.”
I tried to call the local Cox tech-support number, to see if the issue was with my home landline & I get the same message!

I make these calls from my contact list as opposed to manually dialing them so, no dialing errors.

When this persisted for a couple of days I went through my contact list and tried most of the numbers & about 75% of them worked and 25% I got the same Verizon wireless message. No pattern as to the area code but they were all local numbers that I had called before and now I could not call them from my cell phone. I called Verizon wireless tech-support and after much trouble was able to speak to a live person who had me restart the phone which I had already done and then they reset a couple of things and nothing helped.

Verizon promised that their I.T. Department would call me but, no one ever did.
The only thing that resetting did was to unpair my phone from my Suunto wrist computer watch and from my vehicles’ Bluetooth.

I had to re-pair everything.

Last few nights I have tried & failed to call Verizon tech support & speak to a live person. I get disconnected whether I call from landline or cell phone since Verizon robo system wants me to chat with their automated tech following a link which they usually do not send & when they do send the link, my typed messages are ignored. I’m certain the automated system will be unable to fix this issue.

One time when I redialed Verizon I actually got that same Version message

“This is Verizon Wireless. The called party is temporarily unavailable.”

I’m very tempted to dump Verizon after 10 years & go with another carrier.
Not just due to this issue but the inability to speak to a live person.