When organic traffic decreases, whether dramatically or slowly-but-surely over time, it’s a cause for concern.
Generally speaking, there are 3 potential sources of the issue - especially for steep traffic drops. They are:
An algorithm update (external factor)
A change on your website - e.g something broke, or a longer term issue was introduced (internal factor)
Some combination of the above.
An SEO Investigation can help you better understand the underlying issue(s) causing your traffic drop, and help you prioritize what changes are needed to turn the trend around. In combination with a solid SEO Strategy, you’ll be better equipped to start growing organic traffic, instead.