Hello Smugsy,
Welcome to Communities.
Is this a fresh install of vSphere 7.0 or upgraded from previous versions?
Can you confirm if other vSAN-related aspects in the UI are impacted?(e.g. Cluster > Configure > vSAN > Disk Management & Cluster > Monitor > Capacity)
There are 2 main potential issues that could be the cause:
- One relating to SSL trust anchors with some good info posted here:
https://www.reddit.com/r/vmware/comments/e4w74j/vsphere_67_u3a_vsan_html5_failed_to_extract/
- Another due to mis-conversion of character case in a required string (I cannot recall off the top of my head what the string was used for but similar issue could occur as a result).
I would start with checking the SSL aspect first, but either way I would advise opening a case with vSAN GSS as there are other potential causes.
Bob