The response you are seeing for the old
.asp pages would appear to be the standard 404 response on your server (or rather a front-end Nginx proxy by the looks). You seem to get the same response regardless of what non-existent page you request. So, this is not limited to
.asp pages. This 404 response is a "domain holding" page with external third party adverts - which is not desirable, but maybe something which is forced on you by your host?
Edit: Whilst requesting other 404 pages I occasionally got a "502 Bad Gateway" or "503 Service Unavailable" response. This is also not desirable (and not normal).
You need to check with your host what is going on here.
You do not need the old site to be present in order to implement redirects from the old URLs. That is the whole point of an external redirect.
The host said that they "migrated the site to a linux server from a windows one ... so as to be able to use htaccess". This would imply you are being migrated to Apache (or perhaps LiteSpeed).
I assume this is a "shared" server. In which case
.htaccess files should already be enabled.
.htaccess file exists in the document root of your site, then the
Redirect directive you posted in the question, namely:
Redirect 301 /studio.asp /studio.html
really is all you require to redirect from
If this is not happening, then again, you need to query this with your host.
UPDATE: My host provider reckons it's because I have the
.rtf extension on the file as the file is enabled. The thing is, I deleted it on my desktop so it just shows
.htaccess but it still shows as
.htaccess.rtf when uploaded to the server. ... I've used TextEdit on the mac.
Yes, that is certainly a problem! If the file is called
.htaccess.rtf on the server then it's simply never going to be processed by Apache and it won't do anything (which is the behaviour you are seeing - nothing). It must be called
.htaccess - no more; no less with a dot as the first character. But also, it must not be formatted as an RTF (Rich Text Format) file. It must be "plain text", preferably UTF-8 encoded.
Make sure that your Mac is displaying file extensions:
Make sure TextEdit is configured to edit plain text files:
Recreate the file locally with the correct filename. Delete the incorrectly named file on the server and reupload!
(How did you edit and upload all the other files on your site?!)