I'm trying to send out a promote email tonight to the booster club i'm president of, but I got this message "Email Sent at Invalid date at Invalid date"  I've seen this same message in the community here, but I haven't seen anything that indicates how it is fixed. 

I tried sending it twice, but the same thing happened.  See the image below.  If there's a choice, I would prefer that only the first one went out.

Please let me know how to fix this.  Thanks.  Michael