MFP and Renpho Health app?

Has anyone successfully connected MyFitnessPal to the Renpho Health app? I'm looking to use this to directly sync my smart scale's readings to MFP instead of the way I have had to do it for too long, going through the FitBit app. On the Renpho Health side, I successfully enabled the connection and authorized what needed to be authorized, but when I try on the MFP side, it first has me enter credentials for MFP which seems to work OK, but then it opens a page in the phone's default browser (tried using OS-installed Chrome and Firefox as defaults, no difference) to authenticate the Renpho side. Entered credentials there, and it puts a small "Success" block on the window but the window now shows the login form for Renpho. Went back to the MFP connected apps and it shows just my other connection, Google Fit, no sign of Renpho being connected. Went back to the list of possible apps to connect, picked Renpho Health, and it offers to let me connect but no sign that it is connected. Repeat, same result. Kill and restart everything, same result.

The phone is a Google Pixel 6 Pro running stock Android 12 with the March 1 update.

Thanks in advance.