By Default attachment will be stripped in Horde sent Email Box, if you have sent an email with the attachment.
Please refer to the following steps to fix this issue.
- Login to cPanel.
- Go to Email Accounts.
- Login to Horde Webmail email account which sent attachment issue needs to be fixed.
- Click on Settings >> Preference >> Mail.
- Click on Sent Mail.
- Select Save Attachments from Drop-Down and Click on Save Button.
Now, you will be able to find your attachments in sent email as well in Horde.