There are many factors that may influence your car insurance rates for various reasons that all add up to a single factor: your risk.
Insurance providers calculate premiums primarily based on 1) how likely someone is to file a claim and 2) how much risk the provider will face by insuring them. 
For example, say you have a poor driving record and apply for car insurance. That insurance provider will see your driving record as an example of how likely you are to get into another accident and file a claim. If you have a history of accidents, you are seen as more likely to be involved in another accident in the future. This will affect how much you pay for car insurance as the insurance provider tries to balance out the risk of insuring you.
Credit scores work similarly although for different reasons. A credit score does not necessarily affect your ability to drive, but that is not the only risk you present. Instead, insurers generally view your credit score as an example of how reliable you are when it comes to paying your insurance premiums in full and on time. Your credit score is affected by your other bills, so when you miss a payment, you may see a drop in your credit score. This is why you can have trouble finding insurance if you have a low credit score.
Can You Get Insurance with Low Credit?
While it may be difficult, you can still find auto insurance if you have a poor credit score. However, you will likely pay higher insurance premiums than you would with a higher credit score.
Be sure to get quotes from multiple insurers and ask insurance agents about ways you can save money in different areas. Even with low credit, you may qualify for discounts such as Good Driver discounts and Good Student discounts.
You can build credit by paying off debts such as credit cards and student loans when possible. You may also save money by setting up automatic payments. Setting up an auto draft for car insurance can prevent you from missing payments and save money by cutting out unnecessary administrative costs.
Not all auto insurance policies are created equal. No matter your credit score, shop around and speak with insurance agents to find the best policy for you, your budget and your vehicle.