You have paired the wireless siren with the alarm panel and it is not sounding!!
Important Message! Please enable Siren alarm & Local alarm Settings
To ensure your siren activates when the your alarm system is triggered, please enable the "Siren alarm" and "Local Alarm" settings after connecting this Siren to the OSI Alarm System Gen 2. (see illustrated steps below)
This can also be done through the Smart Life App: Select the OSI alarm device >> Select Settings >> Ensure "Local alarm" & "Siren alarm" are enabled
Related article: How to reset and re-add the Gen 2 Wireless Siren