org.apache.commons.lang3 not recognized in my Intellij IDE

Hi, I've imported a method that uses 

org.apache.commons.lang3

however my IDE shows that its not recognized but the code still works perfectly fine, I just find it annoying since it's showing I have errors in my project when I don't. (The app still compiles fine etc. my IDE just states that it cannot resolve symbol commons)

cannot resolve symbol 'commons'

 

 

 

What build system do you use? If it's Maven try to perform the following steps:

• File | Invalidate Caches... | Mark first two checkboxes | Invalidate and Restart
• Close the project window File | Close Project and IntelliJ.
• Open your project in OS file explorer and remove all *.iml files and the .idea folder from your project.
• Delete .m2 maven folder.
• Re-import the project into IntelliJ from Existing sources.