After installed Office Web apps and once completed the configuration , i noticed that i was getting error on all the site collections on the farm:
Workaround / Solution
<staticContent>
<mimeMap fileExtension=".atomsvc"
mimeType="application/atomsvc+xml" />
<remove fileExtension=".svg"
/>
<mimeMap
fileExtension=".svg" mimeType="image/svg+xml"
/>
</staticContent>
<staticContent/>
</system.webServer>
This is because the web.config file has been changed and we need remove the <staticConent/> with red color.