I want to send data to my webserver. If I insert the IP address of my webserver it works perfectly (AT+CIPSTART="TCP","IP","port"). But If I want to use it with the domain name (AT+CIPSTART="TCP","","80'") it doesnt work. But I know what the problem is: The "-" causes the error. I have tested it with another website: for example my website: And it works. I could connect. Any ideas how I can reach my webserver. My webserver works perfectly. I can receive data from another computer so the webserver itself is not the problem.