There is no limit on the number of times you can appear in the FMGE. You can reappear for the exam as many times as you want, until you pass. The FMGE is conducted twice a year, in June and December, so you have two chances to pass each year.
However, it is important to note that the FMGE is a challenging exam, and only about half of all candidates pass on their first attempt. It is important to prepare well for the exam and to practice regularly. There are many resources available to help you prepare for the FMGE, including online courses, study guides, and practice tests.
If you do not pass the FMGE on your first attempt, do not be discouraged. Many candidates have to reappear for the exam multiple times before passing. The important thing is to keep trying and to learn from your mistakes.