ESP8266 server only serves page once, sometimes twice

Nothing. Request handler executes w/o errors, but the browser just hangs and nothing happens.
I waited 5 minutes between two requests and it just does the same thing.

Before the first request:

HTTP server started
+CIFSR:STAIP,"10.0.0.2"
+CIFSR:STAMAC,"18:f
e:34:fd:b8:5f"
OK
CIFSR failed: +CIFSR:STAMAC,"18:fe:34:fd:b8:5f"
OK

First request:

0,CONNECT
+IPD,0,304:GET / HTTP/1.1
H
ost: 10.0.0.2
User-Agent: Mozilla/5.0 (Windows NT 10.0;
 WOW64; rv:38.0) Gecko/20100101 Firefox/38.
0
Accept: text/html,application/xhtml+xml,a
pplication/xml;q=0.9,*/*;q=0.8
Accept-Lan
guage: hu-HU,hu;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Connection:
keep-alive
"HELLO WORLD (1436085723627.167724609377)"
>
busy p...
busy p...
OK
>
>
SEND OK
0,CLOSED
OK

Second request:

0,CONNECT
+IPD,0,304:GET /
 HTTP/1.1
Host: 10.0.0.2
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64;
rv:38.0) Gecko/20100101 D@yÐP
¬Ì ñÿÿÿðÍ cation/xhtml+xml,applicatio
n/xml;q=0.9,*/*;q=0.8
Accept-Language: hu-HU
,hu;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Enc
oding: gzip, deflate
Connection: keep-alive
"HELLO WORLD (1436085950000.67041015625)"
>
busy p...
busy p...
busy p...
>
busy p...
busy p...
busy p...
busy p...
>