I'm 43 had my tubes tied 17 years ago never late on my period till this month only other times I've been late is when I got pregnant.

Anovulation? Since this hasn't happened before, its worth getting a pregnancy test. There is a small risk of pregnancy after a tubal ligation. The most likely cause is a month where you didn't ovulate. This is fairly common during the 10 years prior to menopause (when you stop ovulating) so it probably isn't the last time it will happen. Its usually not serious. Best wishes!