No dial tone after installing new modem

Hello

 user_phs00d

, thank you for reaching out via our Xfinity Community. I'm so sorry to hear your landline phone isn't working after upgrading your modem. That's definitely a frustrating situation, especially when you rely on your landline. I understand how important it is be able to call out. To help me troubleshoot the issue and get your phone working again, could you please tell me a little more about how your phone is connected?

Specifically:

• Is your landline phone plugged directly into the back of your new modem?
• Or is it plugged into a standard phone wall jack?

Knowing how it's connected will help me narrow down the potential causes and guide you through the right steps. I'm here to help you get this resolved as quickly as possible, and I appreciate you working with me to figure this out.