Macro to update off days in a tracker

[seemap]

Hello,

i am trying to build a tracker which allows the employee to mark the weekly off of their choice.

Conditions set is 1. Maximum 8 employee allowed to be on off for a particular day. 2. An employee cannot have the same day off for 3 rolling weeks. for ex., if an employee has marked monday as off for week1, he should not be allowed to have the monday off for week 2 and week3, the application should throw an error

Please look into the sample file attached and help me solve the error.

Regards
Seema