Hi @Irshad!
The scikit-learn version (0.21.2) used to generate this artifact does not match the current version of scikit-learn installed (0.20.2).
Scikit-learn requires you to use a classifier that was trained with the same version as scikit-learn that you're using to run your command. This protects your analysis from unexpected behavior. If you are using a pre-trained classifier from the QIIME 2 docs, make sure that the version of QIIME 2 you're using is the same as the version of the docs you downloaded your classifier from.
qiime info will let you get the version of QIIME 2 you're using, and you can get the correct version of the docs by using the correct version number in this URL:
https://docs.qiime2.org/{version-number}/data-resources/
For example:
https://docs.qiime2.org/2020.2/data-resources/
Even better, ask your sysadmin to install the latest version of QIIME 2, and then you can use the classifier from the current docs. 
Best,
Chris