Wifi is restarting without the reason.

[filipESP]

I have a project, which connects to wifi and sends from time to time
data to server. Sometimes esp log this info:

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1. I (54056579) wifi:state: run -> init (ce00)                                    
2. I (54056579) wifi:pm stop, total sleep time: 0 us / 909284818 us

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but I can't guess why it occurs.
I try to use esp_wifi_set_ps( WIFI_PS_NONE ) function after call esp_wifi_init(), but it still happen.
What is the reason of this behaviour?