Hi Steven,
First off, let me welcome you to the Method forum!
I gave this API call a try on my own account using similar values to what you provided and ended up with a similar result. The URL I received was just a string of random characters. I believe this was meant to return a complete URL, but for some reason, that's not what's happening.
Fortunately, you can get around this by changing one of the values in your API call. If you change "DomainLinkOrMIurl = link" to "DomainLinkOrMIurl = miurl", then the result will be a complete URL, which directs to the correct screen and record.
Give this a try and let me know if it works for you. I hope this helps.
--Audisho