Voicemail set up

[pensnsox27]

I activated a new SIM card for my BYOP Samsung Galaxy S7. I cannot get my Youmail account set up. When I enter the MMI codes, I get an MMI error code.

Also, when I try to set up a regular voicemail account by dialing my own number, I get a message saying " the wireless number you are calling is unavailable.

I would prefer to get the Youmail forwarding figured out so I can use Youmail, it has always worked for me until now. But if the forwarding issue cannot be
resolved, I need to find out how to set up a regular voicemail account.