Is the ESP8266 now receiving data?
Without the ESP8266 connected, you should see something like this in the Serial Monitor
OpenEnergyMonitor.org
ct1:0.00,ct2:0.00,ct3:0.00,ct4:0.00,vrms:0.00,t1:23.75,t2:300.00,t3:300.00,t4:300.00,t5:300.00,t6:300.00,pulses:1
ct1:-0.00,ct2:-0.88,ct3:-1.75,ct4:0.00,vrms:0.65,t1:23.75,t2:300.00,t3:300.00,t4:300.00,t5:300.00,t6:300.00,pulses:1
OpenEnergyMonitor.org
ct1:0.00,ct2:0.00,ct3:0.00,ct4:0.00,vrms:0.00,t1:300.00,t2:300.00,t3:300.00,t4:300.00,t5:300.00,t6:300.00,pulses:1
ct1:0.00,ct2:-1.32,ct3:-2.66,ct4:0.00,vrms:5.13,t1:300.00,t2:300.00,t3:300.00,t4:300.00,t5:300.00,t6:300.00,pulses:1
ct1:0.00,ct2:0.44,ct3:0.90,ct4:0.00,vrms:0.65,t1:300.00,t2:300.00,t3:300.00,t4:300.00,t5:300.00,t6:300.00,pulses:1
That is what you should see. 
Is that sending at 9600 baud?
Have you changed the ESP8266 to 9600 baud?
Now, when you connect the ESP8266, it might work. 
Serial.begin(9600); // Do NOT set greater than 9600
digitalWrite(LEDPIN, LOW);
Serial.println(F(“OpenEnergyMonitor.org”));
i buy the emonesp direct in the shop inkl. programming
But did you specify that you would be using the 3-phase sketch in the emonTx? If you did not, then it will be set to the default value - I believe it might be 115200 baud. The sketch cannot work at that speed.
If it is wrong, you must change it. The information you need is on Page 3 of the documentation, or I think @Simsala might be able to help you there.
hello ! i share the out ! - Danke für die Hilfe
Hi, it seems every thing is working now?
Ich denke, aber ich weiß es nicht, dass dies der Fall sein könnte.
Sorry no
Both @Simsala and I did not understand your last post.
Do you think the problem is that you do not know how to change the baud rate in the emonESP?
@glyn.hudson has created a compiled version of the emonESP firmware for you:
https://community.openenergymonitor.org/uploads/short-url/zegtvp5lICQT1w6J7ZoTXRnsiw3.bin
You can load this into your emonESP and hopefully this will solve your problem.
This has baudrate changed to 9600 in Line 41 of EmonESP/src.ino at master · openenergymonitor/EmonESP · GitHub
This is no longer correct. The software has been changed - the new location where the baud rate is set is
(Source: Glyn Hudson - 15/11/2021)
Thanks - I do not understand anymore. The emonESP was ordered in the shop, so should the emonESP already be finished or am I wrong?. I think that I just have to flash for emontx3.
The emonESP ordered from the shop is suitable as supplied when the emonTx uses the default UK single-phase sketch. The baud rate of both is set at 115200.
The three-phase sketch does not work properly when the baud rate is set to the default of 115200, it will only work properly when the baud rate is set to 9600 (or less). Both ends of the serial link must use the same baud rate, therefore you must change the sketch in the emonESP to work at 9600 baud.
To make your emonTx work on the 3-phase sketch and use the emonESP you must upload new sketches to both. You have already uploaded the new sketch to the emonTx, you must now upload a new sketch (post nr.31) to your emonESP.
Der im Shop bestellte emonESP ist als geliefert geeignet, wenn der emonTx die UK-Standard-Einphasenskizze verwendet. Die Baudrate von beiden ist auf 115200 eingestellt.
Die Dreiphasenskizze funktioniert nicht ordnungsgemäß, wenn die Baudrate auf den Standardwert von 115200 eingestellt ist. Sie funktioniert nur ordnungsgemäß, wenn die Baudrate auf 9600 (oder weniger) eingestellt ist. Beide Enden der seriellen Verbindung müssen dieselbe Baudrate verwenden. Daher müssen Sie die Skizze im emonESP ändern, um mit 9600 Baud zu arbeiten.
Damit Ihr emonTx mit der 3-Phasen-Skizze funktioniert und das emonESP verwendet, müssen Sie neue Skizzen in beide hochladen. Sie haben die neue Skizze bereits in das emonTx hochgeladen und müssen nun eine neue Skizze (Beitrag Nr. 31) in Ihr emonESP hochladen.
Excellent, I wanted to do this as well, but didn’t have time for it yet.
We should also explore the possibilities of changing the baud rate directly via the web interface of the emonESP.
If this isn’t possible, can the “slow” sketch be linked so that it won’t get lost in the forum?
Or if there is a spare IO on the esp, code it so that a pin can be shorted to ground to put the esp serial port in slow mode? One FW for 2 applications (different bauds) with no additional complexity in the GUI, just add the link if using the 3ph sketch.
In the first line of the code there is a constant saying this.
const int version = 14; // The firmware version 1.4
should I change to.
const int version = 16; ?? maybe is just for DEBUG issues
Yes, it should really be 16 (1.6)
The comment at the top of the sketch is the real version indicator.