To Solve the Issue Cannot Continue this Authorization  Flow, Your Current role has insufficient permission.

Scenario

To  fetch the theme or Extension we need to Create New Token, but while Creating New Token we will see the Above error message.

Solution 

Open terminal 

install npm

before Fetching the theme,Run below Code

npm i oauth1 suitetalk

Now Write Code for Fetch: gulp theme: fetch

Create new Token 

Now it will redirect to Browser 

Login to Netsuite using ID and Password 

Now we can see our error message is Solved 

Click on Allow