6554 - There is an entry in box [YTR1.1A]. Please complete box [YTR1.1B]. ABS-19

Absolute Tax Online Filing Errors SA100, SA800, SA900  

This error suggests that on the individual tax return form you have added and completed supplementary pages for employment and crossed on the return to say you have included these pages but not completed the number box with the number of sets of supplementary pages.