The Salesforce user connected to your Soapbox site requires access to associated record types in order to convert transactions properly. If the user connected to the API through Soapbox does not have the right record type permissions, you may run into the following:
1) An error message that says "Record Type is Unavailable" when trying to add a Soapbox Donation or Registration lead to a campaign through Salesforce (screenshot below).
2) An error message that says "Salesforce Error: sbxe1.sbx_EventsCampaignMember: execution of AfterInsert caused by: System.DmlException: ConvertLead failed. First exception on row 0; first error: UNAVAILABLE_RECORDTYPE_EXCEPTION, Unable to find default record type:  (sbxe1)" when trying to complete a Soapbox Donation or Registration (screenshot below).
To resolve, log into your Salesforce account and navigate to the Setup area. The steps from here will vary a bit depending on whether or not your organization has enabled the Enhanced Profile User Interface and/or Improved Setup User Interface (as selected in the User Interface options).
Standard Setup and User Profiles interface:
- Go to Setup > Administration Setup > Manage Users > Profiles
- Click on the profile of the user in question, and scroll down to the record type settings
- Make sure Soapbox Donation and Soapbox Registration are assigned for Campaign Members, Campaigns, Opportunities, and Leads. Note that they do not need to be the default.
Enhanced Setup and User Profile interface:
- Go to Setup > Administer > Manage Users > Profiles
- Click on the profile of the user in question
- In the Apps section, click on the Object Settings link
- Check each of the objects Campaign, Campaign Member, Opportunity and Lead to make sure all required Soapbox record types are assigned. Note that they do not need to be made the default.
Note: If all of record type permissions look good for the API user's profile, be sure to check whether the user has any Permission Sets assigned as these will override the permissions of the assigned Profile and could lock down access to record types further.