If you execute a trigger and it ends with an error, the first place to go for troubleshooting is the log.
You can open the log for a trigger either via the start page. By clicking on the corresponding trigger in the trigger history or via the trigger tile in the trigger menu.


In the log, you can see the history on the left-hand side, i.e. when the trigger was executed. If you select one of the entries, you will see the log entry in the middle for each action that was executed.
If the symbol in the history is coloured red, the trigger ended with an error. If you are looking for the error, you should look at the last entries of the failed action. There you will find the error message and any additional information.