Pulse send email now failed

I was setting up a daily pulse to send out query results, and wanted to test it first. However, as can be seen in the screenshot below, it is explicitly stated to have failed to send.

FYI, my queries are really long and take a while to run. Would this be the source of problems? If so, would appreciate any suggestion on how to fix this!

Thank you

Hi @minhdaltix
Which version of Metabase?
Have a look in the log for more detailed error message.
If you don’t save the log to a file, it can also be viewed in Admin > Troubleshooting > Log