Banks may periodically request token codes or answers to security questions, even for established connections. These requests are not errors but rather intentional security checkpoints set by the bank. When one comes up during a refresh you start in LedgerSync, LedgerSync can show a pop-up so the question can be answered.
The pop-up is titled Please answer the question. It shows which connection the question is for and the bank's question.
If you close the pop-up instead (with Close, or with the X at the top on pop-ups that have one), the refresh is cancelled.
When a MasterCard connection asks a security question while statements are being refreshed, the pop-up can also show an SMS Client button, so your client can answer the question by text. The button appears only when all of these are true:
The pop-up for transaction refreshes does not offer SMS Client.
To text the question:
LedgerSync then checks for your client's reply every 10 seconds for about 5 minutes. The checking runs in your browser, so keep LedgerSync open while you wait.