How do I share a photo as an email using my Textra App?

[Android Central Question]

I am using Textra as my text app on my android phone. I would like to send photos from my phone to someone's email address. I select the photos and select "share as email" and enter the person's email address and hit send. However, I get a message saying "Message failed to send" (error code: 550 5.1.1. I tried sending to different email addresses but get the same error message.

Does anyone have a solution? Thanks