Publishing gem https://rubygems.org

I am trying to build a cli ruby gem. Everything is ready, just need to publish it.

First I tried this,

Enter your RubyGems.org credentials.                                                                                                                               
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   Email:   hima.chhag@gmail.com                                                                                                                                   
Password:                                                                                                                                                          

Signed in.                                                                                                                                                         
ERROR:  While executing gem ... (Gem::Package::FormatError)                                                                                                        
    No such file or directory @ rb_sysopen - popular_deals-0.1.0.gem

and got an error, so after doing some research I got to know that I need to make gem first,

So did this ..

 gem build popular_deals-0.1.0.gem                                                                                                                             
ERROR:  Gemspec file not found: popular_deals-0.1.0.gem                                                                                                            
[19:14:21] (master) popular-deals-from-slickdeals.net-cli

But, still getting errors, am I missing anything? what should I do to solve " ERROR: Gemspec file not found: popular_deals-0.1.0.gem " error? I do have "popular_deals.gemspec"

Thank you so much for your help!

This problem is solved. It was my fault, I needed to build gem with my gemspec file. So, the command gem build pupular_deals.gemspec worked!