Validation Viewstate error
<p>I got this error when I tried to call a <code>OnClick</code> in my form </p>

<p><strong>Error:</strong> <code>Failed validation of viewstate MAC. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same &lt;machineKey&gt; validationKey and validation algorithm. AutoGenerate can not be used in a cluster.</code></p>

<p><strong>Code-Behind</strong></p>

<p><code>&lt;form runat="server" id="form1"&gt;
    &lt;asp:Button ID="btnImprimeBematech" runat="server" OnClick="btnImprimeBematech_OnClick" Text="Imprime Novo Bematech"  /&gt;
&lt;/form&gt;</code></p>

<p>I don't understand becaus in others thread here in StackOverflow, some solutions was the action in the <code>&lt;Form&gt;</code> tag, but I don't have any <code>action</code> in my form.</p>

<p>I tried put <code>EnableViewStateMac="false" EnableSessionState="False" EnableViewState="false"</code> in my <code>&lt;%@ Page</code> but still the same error</p>
