We don't have SSO to login Site24x7. However, you can start monitoring your Azure resources by clicking on the Grant Access button in the Site24x7's Add Azure Monitor page. Log in to the Site24x7 client > click on Azure in the left tab > Add Azure Monitor > Grant Access to your Azure Account.
Note: Grant access to your Azure account that has access to the Active Directory tenant and Owner role for the subscription that needs to be monitored.
Product Manager, Site24x7