We've detected the Office 365 SSL certificate is not trusted on your device. We noticed that your device is using a proxy ...

We've detected the Office 365 SSL certificate is not trusted on your device. We noticed that your device is using a proxy server ({0}), perhaps that proxy server is changing Office 365 certificate in such a way that is no longer being trusted on this device (sometimes erroneous proxy server does introduce such issues). Please check if that proxy server has been setup correctly to work with Office 365 services.