Voicemail

Hi!

I am unable to set up a voicemail. I have read through some of the forums here suggesting that I reset my network settings or reset my phone app, but nothing has worked so far. I’ve attached images to show what I am seeing.

When I go to voicemail I only see the “call voicemail” option but when I got to do so, it opens up a loading screen, and then from there says there was an unknown error, and then says the call was failed.

Any help would be appreciated! Thank you in advanced (: