Email Sending Failed - Email Sending Failed: 'from' parameter is not a valid address

[M. Rahman]

I am using mailgun as my mail provider. Clients receiving email perfectly.  Support ticket mails also working from clients and admins.

When clients placing a new order admins not receiving any emails for new order. But, when i am using another mail provider then it's working fine.

Mail log: Admin Email Message Sending Failed - Email Sending Failed: 'from' parameter is not a valid address. please check documentation (Subject: WHMCS New Order Notification)

[glenn]

Facing the same problem here, but for support tickets. Also using Mailgun.

Edited January 19, 2021 by glenn

[MiM]

Same problem here!

I use mailgun.

WHMCS sends without problem but nothing reaches my inbox, neither support tickets nor cron mails