I don't know if this is related to recent Excel online query string param discussions so I'm starting a different thread.
The et
param is being passed by the Excel client but not in Excel online. I have tried both paid and trial (within trial period) Add-ins.
It may be related to this thread also Word online not sending et parameter when user accesses add-in as trial
thanks for reaching out. Our team investigated and looks like we have a bug, and no, it isn't related to that other thread. We will follow up.
I'm facing the same issue with outlook online, it seems that the value of the StoreType value within OsfControl is always hardcoded to "exchange" in https://r1.res.office365.com/owa/prem/16.1569.8.2186260/scripts/microsoft.owa.extensibilitynext.js which leads to undefined _omnexEntitlment when the etoken is retrieved it's always been retrieved with the initial empty string value.
This is a bug of Addin Commands and has been fixed (validation with "Compare and Merge" and "Range Tracker"). Please try it again.