Under Windows 10, using Thunderbird email client for years now.

Shaw email is now returning AUP#SNDR blocking me from forwarding email info I regularly receive from BritBox, as an attachment as it contains pictorial content, from my Shaw email account to my spouse's Shaw email account, as I have done countless times over the years. 

Please fix whatever is going wrong in your email filters!

If content is not acceptable, your spam filters should be stopping me from receiving it on my Shaw email account, not stopping me from forwarding it to my spouse's Shaw email account!