Bad smell when giving AA in a Renault Clio II

Hello
lastly, when you give the air conditioning of my Clio II, a fairly unpleasant smell comes out, as is moisture. They have told me that the evacuation tube of the air conditioner may have been blocked.
Can it be due to this? If so, where does the tube carry, how can I clean it?
If you know any video or way to do it please
thank you

Change the anti poole filter, greetings.