If an affiliate program closes, the links will appear in the Affiliate link list with an affiliate link error.
There can be 2 different scenarios:
The affiliate program has switched to another affiliate network
The affiliate program is closed for good
If the affiliate program has switched to another network you can easily change affiliate network and Program ID for the specific program under the affiliate program tab. Just find the affiliate program and click “edit”
If the affiliate program is closed, you have two possibilities:
You can delete the affiliate program from the affiliate program tab, and the link will just be shown as a normal link in the front end (not earning you commission)
You can chance the links to another merchant. This is easily done in the affiliate link list.