Lease renewal with three tenants only one signed

I’m a landlord in Iowa with an occupied rental property with three tenants. I reached out two months ahead of the lease expiring and one tenant indicated they want to renew. I posted a lease renewal on Avail and the one tenant has signed and setup autopay. I’ve reached out to the other two tenants with no response. We’re approaching 30 days from expiration and they still haven’t signed. My Internet search shows I need to send an urgent message with a 24 to 48 hour deadline. They’ve been good paying tenants and I don’t want to lose them, but I still don’ t have a signed lease.

Can someone please offer a suggestion?