Validation of viewstate MAC failed when going through an iFrame.

The website works great when I use http://wcswanson.net.deig1/ but when I go through an iFrame it produces an error when the user clicks the 'Get Meetings' link button.

I used the information on this link: https://support.microsoft.com/en-us/kb/2915218 to generate this key:

Code:

<system.web>
    <trust level="Full" />
    <machineKey decryption="AES" decryptionKey="FDF630B343B76BC7189A3988BF655BEB463EAE78355AF4C55B9D62C3328825EE" validation="HMACSHA256" validationKey="858C57041DC73975191B9B603FA5F8917E8A546AC0DEBFCF72BCE24D492F23B8F3B632A3D544E5FC10254C5933D8D295FDF42F1F7FF3C975EEDFCAAD845F9894" />

Through the iFrame I get this error:
Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

But the 'Get Meetings' works from wcswanson.net/deig1/.

Suggestions?

Bill

 

Finally I found a work around. Since this website does not need the login feature, I created a simple blank web page to display the meetings. The updates can be used with the wcswanson.net/deig1/ link. By using a simple page, the filter works from within the iFrame, but the updates will not work through the iFrame. The filter does work through the iFrame, but not the updates.