GoKawiilMicrosoft explains how to re-enable disabled EWS API in Exchange Online
Microsoft has published steps for IT admins to restore access to the Exchange Web Services (EWS) API after apps relying on it began failing with login prompts or protocol errors. Admins can either uncheck a block option in the Microsoft 365 admin center's Baseline Security Mode or run a PowerShell command to re-enable EWS within four hours. Microsoft says this workaround only lasts until April 2027, when EWS will be permanently retired.