An owner can request a comprehensive background and credit screening from a prospective tenant. Sometimes these reports will show an error such as an address notification of previous fraudulent association or social security number mismatch.
This is an indicator that your applicant has mistyped their Social Security Number
Fraudulent Activity at a Prior Address
This is an indicator that the previous address provided has associated fraudulent activity. This does NOT mean the applicant was a part or did anything fraudulently but is meant to be used as an alert.
Ultimately it is the landlord's decision on whether or not to rent to an applicant but knowing the reasoning behind some of the more common alerts that might show on a report will allow the landlord to make the most comprehensive decision on their future tenant.