Multisite network migration not creating network

Hello

I have tried a couple of times to migrate a multi-site network to a new URL and server but it fails in the sense that the result is not a multisite network but a single site with just the main site of the network remaining.

Before migrating I created the blank WordPress as a multisite network (but I did not create any of the subsite, just a blank multisite network).

I used the Migration Key method.

Any idea what went wrong ?

Thank you