oEmbed on multisite in single wordpress installation

We’ve multisite on single wordpress installation. For example,

Main site – testsite.com/
Sub site – testsite.com/subsite

Now when I try to embed a blog from subsite into mainsite or vice verca or post of subsite into subsite, it gives the error Sorry, this content could not be embedded.
Also when I see network call I see this error response,
{"code":"oembed_invalid_url","message":"Not Found","data":{"status":404}}

Question link – https://wordpress.stackexchange.com/questions/388820/oembed-in-wordpress-multisite-not-working