Hi Hellen,
Please check if B1iP user is activated or not. To check this you need to follow these steps:
Integration framework --> Control Center-->Configuration-->User Admin IPO-Steps. Ensure that for B1iP (B1iadmin) user active status is true. If it is false than you need to click 'Toggle Activation' button.
Regards,
Agneesh Jain
SAP Intercompany Team