One of your on-premises Federation Service certificates is expiring. Failure to renew the certificate and update trust properties within 13 days will result in a loss of access to all Office 365 services for all users. Update now
Follow the articles below in that order.
1. http://support.microsoft.com/kb/2713898 - On the On-Prem ADFS server, Scenario 1, only PS Commands
Update-ADFSCertificate -CertificateType: Token-Signing
2. http://support.microsoft.com/kb/2647048 - Run the commands in this article.