Looks like you dug that out of the deep archives, @amin! 
In current versions of QIIME 2, --p-confidence -1 has been replaced with the more descriptive --p-confidence disable. Whichever version you're using, it's generally preferable to fix the underlying issue with the taxonomy rather than passing this parameter, as it disables confidence calculation, causing the classifier:
In future, please share details about the error messages you encounter. Without them, it's hard to help. This post discusses one possible underlying cause at slightly greater length.
Depending on what errors you're running into, I'd very likely recommend you switch back to a contemporary version of QIIME 2. 2021.2 is shiny and new, and does a lot of nice things that a two-year-old version cannot.
Good luck!
Chris 