I had the same problem going through Extension Warehouse. However, if you go to Extension Manager in SU 2019 and go through the “install extension” button using the original download file I think it will install. Worked for me.
I had the same problem going through Extension Warehouse. However, if you go to Extension Manager in SU 2019 and go through the “install extension” button using the original download file I think it will install. Worked for me.