Summary
A Retool Cloud workflow built to send an email (originally 'Email04') lost all its work when the editor screen went blank, and now a fresh rebuild with a single 'ToEmailAddress' variable won't run at all.
AI Response
A 'won't run' / 'Workflow failed to run' error most often means the workflow has no valid startTrigger block, so the run has no entry point — confirm the startTrigger exists and use it (or the block's 'Run' button) to execute. To rebuild the email flow reliably, follow the official Workflows tutorial, which walks through wiring a startTrigger to a Retool Email block on Cloud and running it end to end. Note that Retool Email applies a rate limit (120 emails/hour), which is worth keeping in mind once the flow is running. Saving/publishing frequently helps guard against losing in-progress edits.
Sources
Retool Workflows tutorial | Retool Docs
Official step-by-step tutorial for building and running an email-sending workflow on Retool Cloud, including proper trigger setup.
Explains the startTrigger block that a workflow needs in order to be manually run — the most common cause of a workflow that won't execute.
The Community Team is testing out a new automation. Let us know if it's helpful (or not) by leaving a 
, 
, or 
. Or by marking this post as the "Solution"! Let us know if you have any feedback here. 