An error occurred while encrypting a control's callback state

• Sep 27, 2023

Error Description

This error occurs if you host a web application in a web farm and encryption keys for this application are generated at runtime.

Solution

To solve this issue, assign a key value to the machineKey element’s decryptionKey attribute in the configuration file:

web.config

<machineKey 
    validationKey="your-validation-key" 
    decryptionKey="your-decryption-key" 
/>

Refer to the following help topic for more information: IIS 7 Tip # 10 You can generate machine keys from the IIS manager.