I would first start with a phone reset...could be a temporary glitch.Have you tried multiple phone numbers and/or adding a 1+ in front?Last step would be to contact support.....use the chatbot, lower right hand corner chat bubble.
Long distance usage is based on where the phone number is based in. Way back when for example, 613 though mostly in Ottawa also encompassed Kingston. So dialing a 613 number from one place to the other place required putting the +1.
There are factors other than the cell tower that may have changed your signal strength over the past 6 months. These may include new buildings, new interference sources, more users, etc. What kind of area do you live in? Densely populated, typical su...