There are several things to look at:
  1.  Are the Campaign and donation form in LO cross-referenced to the same campaign in CRM? Don't forget to set the designation field when cross-referencing to process recurring gift donations. (Alternatively, see: Process credit cards through Luminate CRM with no cross-references)
  2.  Are the API Permissions set in the API Admin group? Check these settings:
    1.  Support Management > Force API
    2. Offline Donation API > Add and Refund offline donations via API
    3. Recurring Gifts > Recurring API
  3. Is the donation form published?
  4. Does the donation form allow offline donations?