Exclaimer incident

Client side signature fails to apply and the message 'Failed to acquire auth token' is displayed.

Minor Ongoing View vendor source →

Exclaimer is currently experiencing a minor incident affecting UK: Client Side: Signature Application - Office 365 and AU: Client-Side: Signature Application - Office 365 and 1 more component, which began 6h ago. The vendor's full update timeline is below.

Started
May 28, 2026, 08:01 AM UTC
Resolved
Ongoing
Duration
● 5h 31m
Detected by Pingoru
May 28, 2026, 08:01 AM UTC

Affected components

UK: Client Side: Signature Application - Office 365AU: Client-Side: Signature Application - Office 365CA: Client Side: Signature Application - Office 365UAE: Client Side: Signature Application - Office 365DE: Client Side: Signature Application - Office 365EU: Client Side: Signature Application - Office 365US: Client Side: Signature Application - Office 365

Update timeline

  1. investigating May 28, 2026, 08:01 AM UTC

    Engineers are aware of an issue impacting our ability to apply signatures to messages as they are composed, the message 'Failed to acquire auth token' is displayed. There is no impact to email delivery at this time, once the issue has been resolved signatures will start to be applied again. If you have our server-side offering configured, then you will find that signatures are applied to messages after they are sent. If you have any other issues, please contact our support team who will be happy to help

  2. identified May 28, 2026, 12:16 PM UTC

    Our team have identified the issue and are actively working on a resolution. Further updates will follow once a fix has been identified.