A guest sees dates as open on your calendar, but the booking does not complete and the site shows the message "All rate plans are not applicable, as we found business restriction".
Why this happens. The dates may be open, but the requested stay length might not meet the minimum-stay rule set in your PMS for that season. When a stay breaks a PMS rate rule (minimum nights, maximum nights, closed to arrival or departure), the PMS declines the quote and the site shows that message.
What you can do. Check the listing’s minimum-stay settings in your PMS for the dates in question. You can then either adjust the rule there, or tell guests about the requirement up front (for example, "3-night minimum from January") so they select a qualifying stay length. A request that meets the minimum on the same dates goes through normally.