What Documentation in Colorado?

[Bryan O.]

Hello landlords,
I require Renter's Insurance for my properties and I have a new tenant that is about to breach their lease agreement. I have yet to have a tenant do something like this and want to know how to do handle this the right way. They aren't behind on rent, but violating the lease. What is the proper way to notify them that they must have the insurance? Pay or Quit notice doesn't seem to fit...
Here is the verbiage from the lease:
Tenant agrees that all personal property kept on the premise shall be at the risk of the Tenant. Tenant also agrees to maintain at Tenant's sole expense a Renter's Insurance policy, or its equivalent, issued by a licensed insurance company of Tenant's selection which provides limits of liability of at least $100,000 personal liability. Tenant shall list Landlord as Additional Interest on the policy. Proof of insurance is required within 1 month of the date of this agreement or Tenant shall be considered in violation of this Lease.
I contacted them at the 15-day mark via e-mail with no response. I text messaged both of them at the 7-day mark with no response. I will attempt to speak to them in person today or tomorrow, but if not they are in violation in 3 days and I'm not quite sure what paperwork is necessary.