When user clicks on 'Send' button in email client, email is getting send-ignored. Error string says User did not click send even if user did click send button.
system logs shows error as "FAILED TRYING TO EXECUTE ON CONNECTION glide.10 (connpid=347252): INSERT INTO sys_email0051 "
This is caused if there is any on-before business rule on sys_email table with current.update
Remove current.update from on-before business rule on sys_email table (as it's firing on "before" so, it's not needed). This should fix the issue.