Make sure before testing that the test strips are in date. Wrong test strips code - most test strips come with an individual code on the bottle/packaging. This code must match the code displayed on your glucose meter. If the codes don't match you will get error messages. To avoid this problem check every new box of test strips has the same code as shown on the glucose meter. If not, change the code on the meter.

https://dietsdiary.com/blood-sugar-ultra-review/