Recently having issues with images. On request they asked to see the original email which said

(zohomail.com: Error in processing SPF Record)

This is a new issue i have been experiencing since July, I send emails from my work website but images are not showing in Zoho Desktop or Gmail, Yahoo and Hotmail seem to be fine.

when the images are not displayed there is just an empty box with a black outline, no red x or error image symbol, can anybody help me please and explain what i need to do?

It does not happen with every image but most.

Thank you for your help