https://adfslight.oswiatawradomiu.pl/

This is a link for my son's grades at school(some kind of online grades note). For some reason, tp-link is blocking this website and as far as I have tried, 
I couldn't find a way to exclude this website from being blocked in tp-link router options, the only way is to turn off malicious content filter completely. Administrators of the website said that it's fault of either tp-link, or my software antivirus, but I checked my antivirus and it doesn't block the page, it's only the tp-link that is blocking it. 

My question is, is there any way to add an exemption to a specific link in tp-link options?