Hi Nagpai,
Yes you’re right! I also just wanted to give you an update of why it happened in case anybody else comes across this post. The people from Elegant themes told me to go to the ‘Divi help support centre’ in my theme settings on WordPress and enable it.
What this did was disable the 3rd party plug-ins. After i did this, for some reason, my ‘pop up’ window to upload my images had started working again 🙂
Thanks again!!