Our servers are using 3 Host. Inthere, 2 Servers are running IIS Code Website, and 1 Server are runs Storage which contains image and clip mp4. All of Server are running with one DNS name and Alpha SSL was installed in 3 Server. Acting: Client access 2 Servers run IIS Web Code. Then, IIS Server call Storage to reply image, clip into Site component to reply to Client full Webpage. But, when we use Firefox to access page, image and clip could not load. They are empty. Website is full of text with no image. Otherwise, when we use Chrome, Sarafi (smartphone), UC Browser to access page... Website load is OK with full image and clip. Then, we trace network load in Firefox, we found that all of function that call https://image.[domain]... could not work well. Error 404 loading. But, Chrome loaded slower than Firefox, so it could do well. We had recognized Firefox could not call https again with the same host in the same DNS. TCP call other Server in the same DNS had bypassed with certifier SSL. DEV can exam directly via Website https://congan.com.vn, you'll see website with no image... Because it could not parse, could not make connection again with other host in the same DNS had SSL connection. It's means, IIS congan.com.vn could call image.congan.com.vn via https.