Hashtags not populating?

Hi,

I ran an instance of Mastodon end of last year but took it down a moth later.

Now I'm getting back into Mastodon with a new instance, this time running it from Docker.

The last time I ran my Mastodon instance, I pretty much got an e-mail every day to approve new trending hashtags.

Now in my new instance, I got one email and approved one hashtag (#introduction), but since then I have gotten no emails. Also the trending hashtags list is empty. I checked the postgres database and the tags table is full of records.

Am I missing something here? Or should I wait a couple more days?