Please check your Automatch filters. The more filters you have activated the harder it will get to find opponents. Especially once your "Friends" filter is active, the system will only look for Catanians that are on your friend list to start a match.
Please select more or all scenarios in the expansion you are queuing for. The more scenarios you are queuing for the faster you will find opponents
You might be looking for opponents in times when Catan Universe is a bit less frequented. We suggest joining or Discord server and connecting with Catanians from around the world to make up for a lack of opponents in your time zone. https://discord.com/invite/catanuniverse