Integration with ServiceNow

I have been integrating ServiceNow with Azure Active Directory using the classic portal for a while now with no issues. I note that the classic portal will be gone for Azure Active Directory on 30th November, so I have recently tried to perform deployments using the new portal and am facing one issue.

When configuring single sign-on the Configure Sign-on Blade just sits there looking at me and never progresses or times out:-

N.B. Neither the 'Configure Now' button or 'Manually configure' tickbox are active.

If I return to the classic portal and perform this piece then I can return to this blade and it works perfectly.

Has anyone encountered this issue and/or know of a workaround? Otherwise come the 30th November I might be in trouble.

Thanks...