The two issues outside of the Salesforce SSO settings that are most likely contributing to the SSO errors are the clock on the identity provider server being twenty minutes behind Salesforce and the issuer certificate from the identity provider expiring two weeks ago. These issues can cause SAML assertionerrors, which prevent the user from logging in with SSO. A SAML assertion is an XML document that contains information about the user’s identity and attributes, and it is signed by the identity provider and sent to Salesforce as part of the SSO process4. If the clock on the identity provider server is not synchronized with Salesforce, the SAML assertion may be rejected as invalid or expired, as it has a timelimit for validity5. If the issuer certificate from the identityprovider isexpired, the SAML assertion may not be verified by Salesforce, as it relies on the certificate to validate the signature6. The other options are not likelyissues that cause SSO errors. The identity provider being used to SSO into five otherapplications does not affect itsability to SSO into Salesforce, as long as it supports multiple service providers and has a separate configuration for each one7. The default language for the identity provider and Salesforce being different does not affect the SSO process, as it does not impact the SAML assertion or its validation.