Rendering Error Code 4

Hello Forum,  Today I have been getting this Error Code when trying to render, even short clips.

I have been unable to find any specific online help

As an experiment, I opened a different Premiere Pro project and was able to render without any issues.  However, when I reverted back to the problem project, the error recurred. When I try to render different parts of the project, I get the same Error Code 4 but the timecode numbers are different.  I have been rendering within this project for a few days without issue.  So why now?