Cannot manage to install a plugin in SDL Trados Studio 2019

I've tried to install 2 different apps on SDL Trados Studio 2019 : MyMemory and MS Grammar Checker.

Both files upload properly.

But when I try to open the files to install them, nothing seems to be happening.

When I then open SDL and try to do the activation (either in TM lists for MyMemory or in Verification for MS Grammar Checker), there is no presence of the plug-in.

Also in the list of plug-ins, none of these app appear.

Can someone help ?

Thanks in advance,

Johanne