Summarizing from the discussion (above). @Dylan Walkden, Thanks for sharing the info/solution with the community.
Issue: Hyper-V VMs failing to replication to Azure Site Recovery
Error: Event ID: 32022The connection with the server was terminated abnormally (0x00002EFE). Event ID: 68501: The virtual machine couldn't be replicated. Provider error
Solution: The certificate was expired. Steps to renew the certificate: Log into the Azure portal then go to my Recovery Services Vault, then under "Manage" on the left select "Site recovery infrastructure". In this case, replication is from a Hyper-V host, so, select "Hyper-V Hosts" under the "For Hyper-V Sites". In this list of Hyper-V hosts, click on the three dots ("...") on the right for the Hyper-V host with the issues and click on "Renew certificates" in the menu it presents.
Since the Microsoft Q&A community has a policy that the question author cannot accept their own answer. They can only accept answers by others, I' have summarized and posted the solution/answer to benefit the community users to find the answers quickly.