Need help with ESP-01s and Arduino Nano

I did not realize that i must set all manually.

I set fixed IP,Gateway and Mask with:

AT+CIPSTA_DEF=“192.168.1.100”,“MyGateway”,“255.255.255.0”

and i get this:

[19]
___ __ __
/ _ )/ /_ _____ / /__
/ _ / / // / _ / '/
///_, /////_
/__/ v0.4.10 on Arduino Nano

[605] Connecting to MyNetwork
[3815] AT version:1.2.0.0(Jul 1 2016 20:04:45)
SDK version:1.5.4.1(39cb9a32)
Ai-Thinker Technology Co. Ltd.
Dec 2 2016 14:21:16
OK
[4915] Failed to enable MUX
[8111] +CIFSR:STAIP,“192.168.1.100”
+CIFSR:STAMAC,“dc:4f:22:0a:0b:23”
[8119] Connected to WiFi
[18550] Ready (ping: 38ms).

And example with turning led on/of works…nice

But what this mean “[4915] Failed to enable MUX” ?
Is there any waythat IP,Gateway and Mask can be obtained automatically?

For example i make some project but my “Default Gateway” is not the same every time,
or i want to connect my project to another WiFi network(assuming same nameand password) with another Gateway…