We have been alerted by our clients to potential issues with Outlook Web Access and New Outlook following a recent update by Microsoft.

This issue manifests as a long delay with insertion of images when using the client-side add-in to insert a signature containing images.

Support staff at Symprex have reproduced the issue and contacted the responsible product group over this issue.

This issue is under high priority investigation by Microsoft, early analysis indicates the impact extends beyond add-ins to include OWA and New Outlook clients. Initial findings suggest OAuth latency as a potential root cause

Good morning,

Microsoft have identified what they believe is the root cause behind this issue, and as the update below, have applied reverts to configuration, but these will take some time to apply.

The changes are expected to apply over the next 24 hours, and we will be monitoring this to confirm. Internal testing confirms we still expereince the issue internally.

Microsoft's update is as below, as of 5:00am GMT 07/11/25

We suspect the latency issue is due to a high CPU usage regression, which may have caused delays in image uploads. The reverts have already been applied, and a fix will be deployed via fast track shortly. We’ll monitor saturation over the next 24–48 hours and provide further updates.

Good evening,

We received an update from Microsoft advising of a publicly available status page for the issue today.

The update and issue reference are included below; all Siganture 365 services have remained operational during this incident.

An alert has been posted to all customers worldwide about the incident via the Service Health Dashboard (SHD) any administrator can see.

This alert is listed under the following number: EX1183800.

The rollout is currently at 41% saturation and an update to all customers via the SHD is scheduled for Monday November 10, 2025.