Hello,
you need to format the times before you send the mail.
timechart ...|eval Time=strftime(_time,"%Y/%m/%d %T")|table Time,field1,field2
I have updated the answer could you check now?
Doesn't help. In fact, adding fieldformat _time=... on its own is enough to turn _time into 0NaN-NaN-NaN NaN:NaN:NaN, even without the sendmail. 😕