Add new repository - stuck "Loading"

I'm trying to create a firmware ISO for a PowerEdge R710 - I'm following the instructions here to add a repository

https://www.dell.com/support/article/us/en/04/sln310452/lifecycle-controller-lc-firmware-update-error-no-update-is-available-on-any-11g-server?lang=en

But after I click finish to add the new repository, it just stays "Loading" and never finishes. For over an hour now.