After we went on to HANA migration from the next day all our External Punch-Out procurement via SRM NWBC portal are resulting in Security Alert and 405 errors upon clicking on Check-out via Google Chrome and Internet Explorer browsers and our portal team and networking and security teams are working on as well.
Please view the attached screen shot of error and suggest resolution ASAP.
Can you check the Microsoft site and below link it lists some steps to get rid of the pop up .
Also ask your portal/ Basis guys to check if the links can be shared in https instead of http ?
Refer below links :
Let me know if it helps