It goes offline and don't reset

The device goes offline on its own and don’t reset.

This is not enough information to help you out.
When device comes online , what is wifi strength on the app for that device? out of 5 ?
Don’t reset ?

Please call customer care.

This happens with me as well!
when ordered alexa
‘Turn On Dimm Light’

The alexa gets stuck on the command
and when checked in tinxy app it shows device offline

Switch turns on automatically after power failure