First user to connect Leadjet to your Hubspot CRM must be granted enough permissions. You may have to ask your Hubspot admin to change these settings for you.
Go to Settings > Users & Teams and click on the user's line. A panel will slide in from the right.
Under Account > Settings, make sure App Marketplace Access is enabled.
Under CRM > CRM tools, make sure Edit property settings is enabled (this option can be switched off after the user successfully connected to Leadjet).
Once the necessary permissions are live, you can follow the onboarding steps from the Leadjet welcome panel, and grant Leadjet access to Hubspot. You can see detailed instructions from here Getting Started
You're all set! You can check out the features we offer for Hubspot users here Features
If the issue still persists please don't hesitate to contact us directly at support@leadjet.io