Cannot find old mails

Hi,
I am trying to search for certain emails which are a year or more old. However, scrolling down the search results stops after less than an year old mails i.e. the oldest mail I see is like 9-10 months old. Can you please take a look at the earliest as some of these emails had important information for me?

For example, I am pretty sure I had mails with the word "starbucks" in them more than a year back. However, the oldest mail that shows up in the results is in Dec, 2016.

Thanks,
Abhinav.