Something is funky with your ISP's DNS.
There are two authoritative nameservers for 222.137.195.in-addr.arpa.:
222.137.195.in-addr.arpa. 172800 IN NS ns2.lermi.net.
222.137.195.in-addr.arpa. 172800 IN NS ns1.lermi.net.
These two servers are out of sync: NS1 has zone serial 1334308835 and is returning your PTR record. NS2 has zone serial 1330809486 (older), and is not returning your PTR record.
Anyone whose query is (randomly) sent to NS2 will not get your PTR record.
Instruct your ISP to fix this issue and all should be right in your DNS universe.
NS1
; <<>> DiG 9.7.3-P3 <<>> @ns1.lermi.net -x 195.137.222.81
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48514
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;81.222.137.195.in-addr.arpa. IN PTR
;; ANSWER SECTION:
81.222.137.195.in-addr.arpa. 172800 IN PTR wcrop.com.
;; AUTHORITY SECTION:
222.137.195.in-addr.arpa. 172800 IN SOA tr1.turkcealan.com. log\@ramtek.net.tr. 1334308835 10800 3600 604800 3600
;; Query time: 149 msec
;; SERVER: 195.149.85.195#53(195.149.85.195)
;; WHEN: Thu Apr 19 18:26:23 2012
;; MSG SIZE rcvd: 68
NS2
; <<>> DiG 9.7.3-P3 <<>> @ns2.lermi.net -x 195.137.222.81
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 50379
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;81.222.137.195.in-addr.arpa. IN PTR
;; AUTHORITY SECTION:
222.137.195.in-addr.arpa. 172800 IN SOA tr1.turkcealan.com. log\@ramtek.net.tr. 1330809486 10800 3600 604800 3600
;; Query time: 145 msec
;; SERVER: 195.137.223.65#53(195.137.223.65)
;; WHEN: Thu Apr 19 18:26:51 2012
;; MSG SIZE rcvd: 140
Best Answer
I'd try as hard as possible to have the reverse lookup for my email server's IP address resolve to the name it's using in SMTP conversations. It makes life easier.
I don't have any statistical evidence to back this up, but it has been my experience that, from time to time, messages will be rejected by some remote mailers for not having a reverse lookup that matches the hostname used in SMTP conversations. Rather than have to deal with this problem, it's just easier to get the reverse lookup setup right to begin with. For the last few years I've just treated having a consistent forward / reverse lookup as being a requirement so that I don't have to deal with the problem of not having it.