My plugin can’t see my files

Answering my own question just in case someone comes across it looking for an answer. Managed to figure it out!

We have to get the URL as follows, we can’t just reference it like we normally would on a server

plugins_url( 'products.csv', __FILE__ );

The above code returns the information we need, rather than just referencing products.csv

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)