[FreeToastHost] Message Not Delivered

I have tried to send messages to certain Toastmaster clubs and received the following message:

An email security check failed during email processing.

(DKIM Signature Verification: fail (message has been altered))

Emails failing security checks may be blocked in the future.
If you have any questions about this, please visit support.toastmastersclubs.org .

Is there any way to resolve this issue so that i can get in touch with the clubs?

Please follow the instructions when posting to this site. You always need to enter your club number.

Thank you

For future reference you should be aware that any kind of "chained emails" (e.g. forwarding of forwarding) can sometimes look like an altered email by the time we receive it, particularly if it is going through several different email agents.

If you are sending emails to clubs you are not a member of we may block those if they fail security checks.

Thank you for both of your support! I'm new to the system so was unsure of how the e-mail settings work. I will enter my club number if I do join one!