anyone else come across this and is there a way to find out what is causing it?
What client is 192.168.1.91?
192.168.1.91 is a Windows 10 PC. I scanned the system using malwarebytes but it didn't detect anything.
You can try using something like wireshark to see what it's trying to send to the domain, but it's most likely one of the programs you have on your computer.
its definitely something that might have integrated ads in the application, since that website you provided is a URL shortener.
OK found the culprit it was Malwarebytes. I remember adding ouo.io to exclusion within malwarebyte few months ago since its blocked by default but i dont know why it would need to query it every 2 minutes.