@Balaje_Krishnan Hi! I tried with uBlock Origin and Nano Adblocker and both showed the same error. However I rebooted the computer to install my latest Windows Insider updated and the problem went away and I can't reproduce anymore. I don't know if it is related or not, but its fixed for me now.
@Balaje_Krishnan I'm getting the same issue. If I choose "Resume" in the bottom bar, it will complete the download and start trying to install the extension. However when it disappeared from the bottom bar (looks like install completed), actually no extension was installed. (I also checked edge://extensions/ page)
Extensions from Chrome Web Store can be installed without errors, there may be something wrong with Microsoft Store.