Can no longer find a specific older email when I do a mail search!?

I'm searching for a particular email, from a specific contact with a particular content. Before I would have gotten her email, my sresponse even if it were 3 years ago, but now all I get, if anything is the last few emails. Seems like it will only search the very latest emails. Have I inadvertently changed a setting or has Yahoo Mail Plus changed what they offer? Thanks!|||I have two Yahoo accounts. One continues to search fine through old emails; the search for the other account has stopped working in the past week and now only finds emails that have arrived in the past few days since it broke. Search link seems lost to older emails, though they still appear in directories and remain accessible.