It's important to turn off signatures or disclaimers to messages coming into Backup Radar. The reason for this is that most signatures or disclaimers actually modify the HTML/Text email coming in and that would make it difficult for our system to recognize and parse the message. We will troubleshoot and add support for signatures for you to the best of our ability. For the best results please turn them off, if possible.
In your Exchange Admin center click on Mail Flow and then rules.
Edit your rule and add an exception to account for the sending email address or destination so it does not apply your default signature to the message.