@iclou said in Upload of pdf files not working: I have configured "allow users to upload any file" I might be wary of allowing users to upload any type of file. Might suggest you restrict this a bit more unless you have a real use case for any and all file types, sans any restrictions.

I have resolved this issue by adding the following rule to local_rules.xml. <rule id="100014" level="0"> <if_sid>31533</if_sid> <url>^/socket.io/</url> <description>Ignoring NodeBB (socket.io).</description> </rule>

ok, I just did a downgrade - now all works fine !! nodejs --version v13.14.0