I’ve double-checked the settings and cannot find any problems, but still the redirects are not working. At this point, I’m not sure if the problem is the plugin or my host, Flywheel (since they have a very specific hosting setup).
Domain A is the primary domain. I have Domain B pointed at the host’s A record. I have Domain B setup as an alias on Domain A’s Flywheel account. I can confirm that Domain B does indeed take you to Domain A. I have configured in the multi-domain plugin for Domain B to point to Domain A/page. I have also checked many times to make sure the entered page is exactly the correct URI (including the preceding /). However, Domain B will not redirect to Domain A/page, it only goes to the home page of Domain A.
I’m also going to contact Flywheel support to see if they can help me with this.