malicious email

I am one of the club officers for Brewery District Toastmasters Club (#621016). We use Free ToastHost with a URL www.bdtm.org
Looks like malicious email are going out from my email ID @toastmastersclubs.org 
Information Security dept of my employer spotted such emails on Jan 7 and April 7. I was wondering whether you are able to do anything to stop it from happening again.

We need the actual full internet email headers to see where the email was sent from. 

Subject: [External Sender] Your personal data has leaked due to suspected harmful activities.Sender:server@toastmastersclubs.org  Recipient:Vengal JacobReply-to:admin@bdtm.org To:admin@bdtm.org Apr 7, 2023, 8:00pm CDT

Please see the attachment

Thank you for the report we have taken step to block that email host.