I installed the HS210 3-way switch and it's working physically just fine at the switch and also at the other end using a standard 3-way switch. Using the app the switch turns on just fine but takes 2

I have hooked up HS210 to line with travelers, neutral and groun (line to black, travelers to top screws (per instructions). Other 3- way (load to light) dumb 3-way switch. Switches work great manuall