This may be caused by running multiple extension that perform functions like: stock checking, checking ranking or reviews of a product
Solution: Complete the captcha challenge request (fill in the letters in the text box) and then disable your all Amazon related chrome extensions that might be running at the same time attempting to get Amazon stock, ranking, reviews.
We do not recommend running multiple Amazon related Chrome extension while running AZInsight as it may trigger Amazon's system to flag you and present you with the captcha page.