Dealing with AT+CIPSTART errors

[dbrgn]

Connecting and sending data works initially:

AT+CIPSEND=1,172

OK
>
PUT /sensors/people_now_present/ HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Content-Length: 7
Host: status.crdmp.ch
User-Agent: Nixie counter

value=1

Recv 172 bytes

SEND OK
+IPD,1,518

...but after some delay the connection is closed.

1,CLOSED
WIFI GOT IP

If I try to send data from this point on, this always fails with the excellent error message "ERROR":

AT+CIPSTART=1,"TCP","94.230.210.85",80

ERROR
1,CLOSED
AT+CIPSTART=1,"TCP","94.230.210.85",80

ERROR
1,CLOSED

Any idea what the problem could be?

(Serial communication captured with a logic analyzer.)

[marius-meissner]

Sounds like a tricky problem. Maybe a bug within ESP-AT? Which firmware version are you using?

I assume you are calling receive() from time to time? Just to make sure that the remote buffer of ESP-AT does not fill up.

Would it be possible to see what is happening at the remote webserver (TCP handshake, etc.)?