Try a manual search on one of the episodes. You can see what sonarr would do in case of an automatic search, e.g. see if it actually returns results, and if all those results have a red exclamation mark, hover over it to see why sonarr rejects it for automatic downloading. This can be various settings. Size, quality, ignored words, …
You can’t add them yourself. Aliases are handled here:
Might be an indexer issue. Try a manual search as explained above.
You’ll probably rather want to open your own topic, as it seems nothing is found on your setup?