First error for Asset Record is: FIELD_CUSTOM_VALIDATION_EXCEPTION OBJ: Asset - You must specify the Account for this Asset
(Error message may vary)
In Salesforce, custom validation rules may be configured on Salesforce objects/fields as described in this link: Examples of Validation Rules
Often, data being Inserted/Updated/Upserted may not meet the criteria required by the custom validation rules that are configured in Salesforce.
The criteria is often described within the remaining text within the error, for example:
“…you must specify the account for this object”
“…please enter a customer number in the associated account and ensure the customer is active before proceeding”
Options to resolve this issue are to either correct the incoming data from the source to adhere to the criteria and resubmit if necessary or temporarily turn off the custom validation rule in Salesforce to allow loading of the data