Hi @Darren Brown-A Thank you for reaching out to us on Microsoft Q&A Platform. Happy to assist!
I understand that you have Hyper-V to Azure set up using ASR. However, the connection has failed between the two platforms due to cert expiration. See the snippet below with details to renew and to check certs expiry.
Doc reference: https://learn.microsoft.com/en-us/azure/site-recovery/vmware-azure-manage-configuration-server#how-to-renew-ssl-certificates
Hope this helps. Feel free to reply if you have any questions.
If the response helped, do "Accept Answer" and up-vote it