Hi,
Please add below code in web.config,you can change below httpRunitme attributes like maxRequestLength to required MB(i.e. 8MB,10MB Default is 4MB).
<configuration>
<system.web>
<httpRuntime executionTimeout="90" maxRequestLength="4096" useFullyQualifiedRedirectUrl="false" minFreeThreads="8" minLocalRequestFreeThreads="4" appRequestQueueLimit="100" />
</system.web>
</configuration>
I hope this will help you out.