Server identity, Captiveportal.nokia.com not trusted

I recently started getting pop up messages that say “cannot verify server identity: map-mail.outlook.com”. Under details it shows a Certificate “captiveportal.nokia.com” not trusted, and gives an expiration date, usually within several days. If I take the “more details”option it gives the organization as Nokia Solutions and Networks, a serial number, and all sorts of data under the public key data.

Does anyone know why this started happening just in the past few weeks. It happens if I’m out on a walk, or sometimes in my car. But always when I’m outside away from my WiFi area.