We are aware of external senders receiving bounceback messages when attempting to send email to Firespring-hosted mailboxes. This is only affecting clients whose senders are using a third party security feature: Cisco Ironport email security. A recent Cisco update to this program is causing the bouncebacks. Current workarounds include having the sender send their messages to a non-Firespring-hosted mailbox (several other email providers are also impacted by this Cisco update) or disable Ironport until Cisco resolves the issue. Please have the sender work with their IT team member if they would like to disable the Cisco Ironport security feature until the issue is resolved.
