API error getting contact timeline details



I had a tool built for me that uses the API to pull the complete timeline for a list of contacts that submit with a CSV file. I am new to working with the API and sometime it works like a charm but many times I get an error that starts “Giving Up http://api.hubapi/com/contacts/v1/contact/email/xxxx@xxxxx.com…” Does anybody have an idea what this means and how I can prevent this error from occuring?

The frustrating thing is that it is intermittent.