Approval Matrix not working in Email, which is sent through SOST

Dear Gurus,

In a SO, approval matrix not working properly, I have checked in SOST for answers, but don't have a clue.

Will highly appreciate suggestions/solutions on how to check this error.

***Elaborating the background of this process, this is used for PAM approvals after saving a SO, which is then sent to Business head's mail ID for approvals through mail, when the sap ID of Business Head's maintained in customer master, partner function.

I have checked from my side but don't have a clue.

PFA

Thanks & Regards,

DB

pic 1 of sost

pic 2 which came in mail