I would suggest using mqttexplorer and see if something looks fishy. I only have seen wildcards used in configuration.yaml using the file editor. Wildcard is a “+” in yaml
Troubleshooting MQTT? MQTT-Explorer can help you be successful!
If you have Add-ons available, try adding this Add-on repository to your Add-on list. GitHub - GollumDom/addon-repository.
With this you can see that the broker sees and likely find the bug.
HINT: I have found using this, if you look at the JSON string and it is in color, the JSON is valid. If it is monochrome, the JSON is invalid and it will not work.
You can also go into integrations and begin disabling them one by one until the error goes or disable them all and renable them all one by one until error occurs.