The unsolved lines will have to be deleted and handled after the reconciliation.
A match must be found in the bank account ledger entries, and if there isn't one, the line must be deleted.
A clue to correcting it can be found in the No. of Reconciliation Suggestion or Additional info, and then matched manually to a bank account ledger entry. If there isn't a match found anywhere, a journal line must be created and then handled from the general journal.
An unsolved line is a sign that the statement file is incorrect. You must delete it and import it again.