Sure. The letter you received is meant to notify you that your insurance coverage has ended, and DMV hasn't received any new insurance coverage notification from any other company.
Do you have insurance already?
Yeah, in fact, i have one.
Then, do not worry about. Just follow the proper procedure written down in the letter and contact your insurance company or agent, to talk about the problem. Most probable thing would be to ask your company to file a notice of coverage with the DMV via electronic.