Unable to install custom app on client's store

Hey Shopify Brains Trust!

I have created a custom app for use on one of our client’s stores using my workplace’s Shopify Partner account.

I have generated an install link and have provided that to the client, however when they navigate to the install link, they are sent to their apps list in the admin panel, without any way of installing it.

I have seen some other posts on here from a couple of years ago with the same issue, however none of the resolutions that worked for them are applicable in this scenario.

Has anyone experienced this problem recently?

Kind regards,

Josh