Migrating from 1 server to another issue

Hi Team,
We are migrating our website backup have been restored but i am not able to install custom app. Please help me with that.

I have tried below commands:

bench install-app sky_custom.zip

bench --site site1.local install-app sky_custom.zip

Below are Old and new server erpnext details:
OLD Server:
Installed Apps
ERPNext: v12.11.2 (version-12)
Frappe Framework: v12.9.1 (version-12)
Sky Custom App: v0.0.1 (master)

New Server:
Installed Apps
ERPNext: v12.14.0 (version-12)
Frappe Framework: v12.12.0 (version-12)

Is the custom app in your apps folder?

Verify by running from your frappe-bench:

ls apps

In Old server or in New Server?

In old server it is.
but not in new server.

the error is that bench not able to find the zip file, can you make sure you made the command from the directory of which you have the zip file or you have at least copied the zip file to the correct directory.

You have to install the app on the server first using get-app

bench get-app <link_to_sky_app> 

After this you can install it on the site.