My guess - the certificate expired on your AD controller.  Are there any certificates on your AD controller that have expired around that time?   Pro-tip.  If you have Office 365/Azure AD/Entra ID - authenticate against that. https://documentation.meraki.com/MX/Client_VPN/AnyConnect_on_the_MX_Appliance/AnyConnect_Azure_AD_SAML_Configuration ... View more