Hi pfrodrigueztorres, Don't Reset your master password. You will lose all of your logins & passwords if you don't back them up first.

Have you tried Removing or Changing your master password?

This article covers Master Passwords: Use a Master Password to protect stored logins and passwords https://support.mozilla.org/en-US/kb/use-master-password-protect-stored-logins

The Firefox Password Manager

securely stores the usernames 

and passwords you use to access

websites and then automatically fills
them in for you the next time you visit a website. 

This article will show you how to use the Password Manager to remember

https://support.mozilla.org/en-US/kb/password-manager-remember-delete-edit-logins

My_Cheese_Is_Slippin' said

Hi pfrodrigueztorres, Don't Reset your master password. You will lose all of your logins & passwords if you don't back them up first. Have you tried Removing or Changing your master password? This article covers Master Passwords: Use a Master Password to protect stored logins and passwords https://support.mozilla.org/en-US/kb/use-master-password-protect-stored-logins

Yes I tried everything and it always says incorrect password but I am certain it is that one.

Double-check that your MP is correct.

My security software blocked Firemaster.

Take a look at this thread. You might find some help there: https://support.mozilla.org/en-US/questions/1271656

Also, this one:

https://support.mozilla.org/en-US/questions/1268335