Photon flash blue but cannot be seen after more than 1 month running

I have my photon running on-line for weeks. I recently started to have connections problems. Then tried to reconnect (go in flash blue) using the phone Particle app.
At this point I already can see some problems. Sometimes I can find the photon sometimes I cannot find it. Sometimes I can go up to the WLAN connection, and rather to connect the device flash green fast or return to flash blue.
What can I do?
I am quite sure this device when bad for some reason. Tried to connect to different WLAN in different location. No changes.
Reflashed using the new version. No changes.