By default,if the "Session Level Reject" message is received in replay to the "Resend Request" then this is considered as a serious problem and the FIX connection will be closed. This property allows to change this behavior and consider the "Session Level Reject" on the "Resend Request" as the "Sequence Reset Gap Fill" message.

public virtual bool ConsiderRejectOnResendRequestAsGapFill { get; set; }