You don’t say which version of the ESP core you’re using. There’s a floating point issue that is fixed in the latest version, looks like that’s the likely culprit to me.
I had this hardware working for over a year with older version of Blynk s/w. After I did a massive update of Raspbian and all 3 Blynk applications, it stopped to accept floating point values.
Welcome to the world of change… not all good, but change nevertheless Don’t forget to use the forums search function, this recent (actually resurrected) floating point issue, and the solution, has been discussed a few times.