Most states allow unlimited attempts for online exams. for all other states that require a certain limit, the system will allow you to take an exam 5 times (as allowed per state law). If you do not pass the exam within 5 attempts, you must attempt another exam and will have 5 chances to pass that one as well.
The following list of states allows UNLIMITED attempts for online exams:
Alaksa, Arkansas, California, Delaware, Illinois, Louisiana, Maine, Minnesota, Mississippi, Missouri, Nevada, New Hampshire, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Virginia, Vermont, Washington, West Virginia, Wisconsin