XIAO’s GPIO operates at 3.3V, so the SSR control input must also be 3.3V. Alternatively, a 3.3V-5V level converter is required.
EDIT:
Looking it up on Amazon, I found the following description. It might just barely work with LOW=0V and HIGH=3.3V.
★High Level Module: 0-2.5V state low level relay ON, 3.3-5V state high level relay OFF; Low Level Module: 0-2.5V state low level relay OFF, 3.3-5V state high level relay ON.