The most common reasons a Slack alert doesn't fire are:

1. You've updated the name of the channel in Slack. You'll need to edit your alert in Trevor.io and select the new channel. 
   
   
2. You've modified the Saved Query in Trevor.io. Trevor determines whether to fire your Slack alert by comparing the current results to the previous results. When you modify your query, this process resets and you'll need to wait until the next interval (i.e. the next day or next hour) to see if it fires. 
   
   
3. The first column isn't unique. If you trigger your Slack alert using our "new rows" trigger, Trevor compares the first column in the current results to that of the previous results. You therefore need to make sure your first column is unique. In most cases, you can use an ID column. 
   
   
4. Your query isn't set up correctly. Feel free to chat with our support team, and they'll dig into this for you 💪