ESP8266 webserver port 80 issue

Dear all

i have created a server using Arduino Uno and ESP8266 (AT+CIPSERVER port 80) and the problem is that i have noticed that sometimes the server hangs.

I use a port scanning tool to check if port 80 is available on the arduino and sometimes its not. In addition to that, on the serial messages the AT+CIPCLOSE command sometimes returns a busy message.

Has anyone else a similar issue?