I had previously added a developer as a collaborator. After that we stopped working with them so I removed them. Now we are working with them again but when they tried to send a request for collaborator access it doesn’t work.
First, make sure they are trying to request access using your original .myshopify.com URL, not your custom domain. The partner dashboard hates custom domains for collaborator requests and will often just fail silently.
Second, check your Settings > Users and permissions. If you have “Only allow people with a collaborator request code” turned on, try regenerating the code and sending them the new one.
If they still can’t send it, you can always just invite them as a regular staff member using their email to get them moving while you figure it out.