Thanks for the reply. I was able to solve it quickly adding it.
For anyone in the future, hosting nodebb on a windows server, may also have the same problem. This is how I fixed it
<outboundRules>
<rule name="ForceFileDownload" preCondition="IsXMLorJSON">
<match serverVariable="RESPONSE_Content-Disposition" pattern=".*" />
<action type="Rewrite" value="attachment; filename={R:0}" />
</rule>
<preConditions>
<preCondition name="IsXMLorJSON">
<add input="{URL}" pattern="\.xml$|\.json$" />
<add input="{URL}" pattern="^/assets/uploads/" />
</preCondition>
</preConditions>
</outboundRules>