Hey Stephen,
Thanks for the reply. I have submitted a ticket as well: [RS #CGJ-85812-247] . Most of these sites are using ASP and probably do have the original CP index.html in the root. They should generally all have the directory index turned off and it is this way for accounts on the old server that haven't been migrated yet as well so I'm not sure why this would cause an issue.
If directory indexes are off and ASP is on shouldn't it default to default.asp? I don't recall having to specify this for the sites. I tried removing the index.html page on one site and it appears to bring it back online so I'll try with the others. I agree, the CP indexes should generally be removed.
Thanks!