Thanks for following up with the Community, ri595.
 

I've reviewed our investigation about a Delivery Server Down message appearing when trying to send sales forms and can confirm it's been resolved.
 

One of the reasons this can occur is if your email's subject line contains invalid characters, emojis, etc.
 

Here's a list of accepted characters:
 

• Comma - ,
• At symbol - @
• Ampersand - &
• Tilde - ~
• Asterisk - *
• Space - ( )
• Underscore - _
• Semi-colon - ;
• Plus sign - +
• Single quote - '
• Dot or period - .
• Question mark - ?
• Minus sign/hyphen - -
• Exclamation point - !
• Number/pound sign - #
• Alpha-numeric - A-Z, a-z, 0-9

To confirm your email's subject lines don't have invalid characters, you can use the Gear () icon, go to Account and settings, Sales, Messages, then delete your Email Subject Line. Afterwards, you can turn on the Use standard message option and save your changes.
 

If you have no invalid characters in your email subject lines, but continue encountering the Delivery Server Down message, you'll want to get in touch with our Customer Care team and reference the investigation's case number (INV-85689). They'll be able to pull up your account in a secure environment, conduct further research with you, and begin reopening the investigation if necessary.
 

Please don't hesitate to send a reply if there's any questions. Have a lovely day!