@BibhuNayak Please locate “DeserializationFirewallImpl” configuration under configMgr( http://<hostname>:<portno>/system/console/configMgr) and add [ like below.I hope this will help.
@Belinda_Please validate if your GET/PUT services are working fine using Test Model Object.Please refer to the video at [1] .[1]. https://helpx.adobe.com/experience-manager/kt/forms/using/Integrate-AEM-Forms-With-Dynamics-365.html