It seems to be a known issue to activate conda environment on windows.
I would like to share my workaround in case could be useful for somebody.
Please be aware that it may not cover your situation (YMMV)
File -> Settings -> Tools -> Terminal -> Shell Path
cmd.exe "/K" for %I in (.) do D:\Anaconda3\Scripts\activate.bat %~nxI
change D:\Anaconda3 to your anaconda install path