nvidya : circular download issue

http://nvidya.nirmavidyavihar.co.in:2500/Pages/BaseFramework/Security/Login.aspx?OrgGroupId=1341
Org: Nirma Vidyavihar Charodi 
Uname:23 
Password:200304 
Issue: In Circular Attachment is not opening it shows error (File Corrupted) for circular named as "Class_XI_HY_QP_Chemistry_26112020"