Users may be unable to view or modify custom forms in SharePoint Online

A post-incident report has been published.

Title: Users may be unable to view or modify custom forms in SharePoint Online User impact: Users may have been unable to view or modify custom forms in SharePoint Online. More info: Affected users may have encountered multiple potential scenarios with Nintex and SharePoint Framework (SPFx) Customizers forms, including: - Blank pages - Null target exceptions Final status: We've completed deployment of the fix to all affected environments, and we've confirmed with impacted organizations that the issue is no longer occurring. Scope of impact: This issue may have impacted any user attempting to view or modify Nintex or SPFx Customizers forms in SharePoint Online. Start time: Monday, October 12, 2026, at 1:00 AM UTC End time: Wednesday, October 14, 2026, at 5:52 PM UTC Root cause: A recent API change to the SharePoint Online infrastructure introduced an incompatibility in how requests from custom forms are processed, resulting in impact. Next steps: - We're reviewing our testing and validation procedures to help prevent similar impact in the future. We'll provide a preliminary Post-Incident Report within two business days and a final Post-Incident Report within five business days.

Title: Users may be unable to view or modify custom forms in SharePoint Online User impact: Users may be unable to view or modify custom forms in SharePoint Online. More info: Affected users may encounter multiple potential scenarios with Nintex and SharePoint Framework (SPFx) Customizers forms, including: - Blank pages - Null target exceptions Current status: We're continuing to deploy our fix to the affected environments and anticipate that deployment will be completed within 48 hours. We'll provide the latest deployment progress and updated completion timeline in our next update. Scope of impact: Impact may be specific to any user attempting to view or modify Nintex or SPFx Customizers forms in SharePoint Online. Start time: Monday, October 12, 2026, at 1:00 AM UTC Root cause: A recent API change to the SharePoint Online infrastructure introduced an incompatibility in how requests from custom forms are processed, resulting in impact. Next update by: Wednesday, October 14, 2026, at 6:00 PM UTC

Title: Users may be unable to view or modify forms in SharePoint Online User impact: Users may be unable to view or modify forms in SharePoint Online. More info: Affected users may encounter multiple potential scenarios with Nintex and SharePoint Framework (SPFx) Customizers forms, including: - Blank pages - Null target exceptions Current status: We've confirmed a recent API change as the source of the impact and have prevented it from reaching any further environments. We're continuing to deploy our fix to the affected environments to remediate the impact. Scope of impact: Impact may be specific to any user attempting to view or modify Nintex or SPFx Customizers forms in SharePoint Online. Start time: Monday, October 12, 2026, at 1:00 AM UTC Root cause: A recent API change to the SharePoint Online infrastructure introduced an incompatibility in how requests from custom forms are processed, resulting in impact. Next update by: Tuesday, October 13, 2026, at 6:00 PM UTC

Title: Users may be unable to view or modify forms in SharePoint Online User impact: Users may be unable to view or modify forms in SharePoint Online. More info: Affected users may encounter multiple potential scenarios with Nintex and SharePoint Framework (SPFx) Customizers forms, including: - Blank pages - Null target exceptions Current status: We’ve isolated a recent API change as the suspected source of the impact. We’ve initiated the process of deploying a fix to confirm our findings and potentially remediate the impact. Scope of impact: Impact may be specific to any user attempting to view or modify Nintex or SPFx Customizers forms in SharePoint Online. Next update by: Tuesday, October 13, 2026, at 8:00 PM UTC

Title: Users can't view or modify Nintex forms in SharePoint Online and receive an error User impact: Users can't view or modify Nintex forms in SharePoint Online and receive an error. More info: Affected users are encountering multiple potential scenarios, including: - Blank pages - 200 HTTP errors - Null target exceptions Current status: We're continuing our analysis of the HAR captures to determine the cause of impact. Scope of impact: Your organization is impacted by this event, and impact is limited to users viewing or modifying Nintex forms in SharePoint Online. Next update by: Tuesday, October 13, 2026, at 1:30 AM UTC

Title: Users can't view or modify Nintex forms in SharePoint Online and receive an error User impact: Users can't view or modify Nintex forms in SharePoint Online and receive an error. More info: Affected users are encountering multiple potential scenarios, including: - Blank pages - 200 HTTP errors - Null target exceptions Current status: We're expanding our investigation to include HTTP Archive format (HAR) browser captures of the issue in progress to assist in isolating the underlying cause of impact and develop a remediation strategy. Scope of impact: Your organization is impacted by this event, and impact is limited to users viewing or modifying Nintex forms in SharePoint Online. Next update by: Monday, October 12, 2026, at 9:00 PM UTC

Title: Users can't view or modify Nintex forms in SharePoint Online and receive an error User impact: Users can't view or modify Nintex forms in SharePoint Online and receive an error. More info: Affected users are encountering multiple potential scenarios, including: - Blank pages - 200 HTTP errors - Null target exceptions Current status: We're reviewing support case details to better understand the impact scenario and determine our next steps. Scope of impact: Your organization is impacted by this event, and impact is limited to users viewing or modifying Nintex forms in SharePoint Online. Next update by: Monday, October 12, 2026, at 8:00 PM UTC

Title: Users can't view or modify Nintex forms in SharePoint Online and receive an error User impact: Users can't view or modify Nintex forms in SharePoint Online and receive an error. Current status: We're investigating a potential issue with SharePoint Online and checking for impact to your organization. We'll provide an update within 30 minutes.