Inside the MAS90\Home folder there is a program called "OITest.exe".  Run that and it will confirm whether BOI is working on that system.

This was done on a v2023 Standard install.

In Company Maintenance, make sure Allow External Access is enabled.

The OITest worked, but the script does not in Std, only in Adv.

Set oScript = CreateObject ("ProvideX.Script")
oScript.Init("C:\\Sage\\Sage100_2023\\MAS90\\Home")
Set oSS = oScript.NewObject("SY_Session") --This is where it fails

Have you tried removing the extra delimiters from the path?  

Yes, either way, same error message

With Unified login enabled (so I don't need to provide credentials):

I ended up reinstalling Sage 100, but the Advanced version and it works. I'm not sure what was going on, but this resolved it for me so I can continue my project. Thanks Kevin.