Issue running builds

I’m new on TravisCI.
I would like to run a basic build with node and docker but I’m getting an error about:

  • We are unable to start your build at this time. You exceeded the number of users allowed for your plan. Please review your plan details and follow the steps to resolution.
    And
  • You exceeded the number of users allowed for your plan. Please switch to a bigger plan

I’ve not used any credit yet