Hi, We have the same issues. I tried connecting the Hubspot account to our current website and I got the error as well. (2 weeks ago it worked)
I tried on another WP and it worked. The only difference between the 2 are the WP version. The one that did worked use 5.9.3 and the other just got updated to 6.0
So I’m wondering if the new WP version is causing the issues.
