I think the question here is; did Volvo unlock the XC40 P8 Recharge in the API the integration is linked to? I have the same issue as you have @jeremyjaytaylor. My app is working, but I get the Unauthorized message in my HA log.
I’ll keep on searching through Volvo’s developers site to see if I can find out which API instance is used for the P8.
-update-
It seems the XC40 P8 Recharge is not included in the API yet. I get an Unauthorized response using Swagger on the Developers site of Volvo:
And there is also a clear statement in the Overview text:
“This API is a Beta release, and as such can be tested against your own vehicle but not published for general release. This API works for all connected cars up to model year 2021, excluding the XC40 Recharge BEV.”