I made a tab for my visualforce page just so I can get it's URL and reference it in a hyperlink in a formula field. Unfortunately since it is a tab, the page moves away from the originating page to the VF tab. How can I reference only the VF page instead of the tab?

Hi, I'm running into an issue with getting an access token using a connected app with grant_type = password.  Here is my curl script:

curl https://test.salesforce.com/services/oauth2/token -H "Content-Type:application/x-www-form-urlencoded" -d "grant_type=password" -d "client_id=<my client_id>" -d "client_secret=<my client_secret>" -d "username=<myusername@domain.com>" -d "<my password+secret>"

I'm getting an invalid_grant error  "Authentication failure"