This could be due to an apex class that is referencing a record that is not valid in the production environment or if an attempt is made in the class to populate an id into a Lookup field of a record that did not exist. When you see this issue, check if there is any bad data.
For example, an ID that is causing the error might be coming from a different org and is not valid in the current org.
If a test class created in a sandbox environment points to a record in production and is pushed through a change set, it will give this error. Replacing the record Id with the sandbox Id should fix the issue.
000385987

We use three kinds of cookies on our websites: required, functional, and advertising. You can choose whether functional and advertising cookies apply. Click on the different cookie categories to find out more about each category and to change the default settings.
Privacy Statement
Required cookies are necessary for basic website functionality. Some examples include: session cookies needed to transmit the website, authentication cookies, and security cookies.
Functional cookies enhance functions, performance, and services on the website. Some examples include: cookies used to analyze site traffic, cookies used for market research, and cookies used to display advertising that is not directed to a particular individual.
Advertising cookies track activity across websites in order to understand a viewer’s interests, and direct them specific marketing. Some examples include: cookies used for remarketing, or interest-based advertising.