Incorrect PTR record for 203.0.113.2 is returned globally: it is set to
mail.example.comin Plesk but global search shows different value:
# nslookup 203.0.113.2
name = some.other.site.
However, Plesk name servers return correct value:
# nslookup 203.0.113.2 ns1.example.com
name = mail.example.com.
digutility shows a name server which returns the incorrect PTR record:
# dig ANY +noadditional +noquestion +nocomments +nocmd +nostats +trace -x 203.0.113.2
113.0.203.in-addr.arpa. 86400 IN NS dns.johndoe.com.
Global DNS records are stored on the provider's side.
Contact the provider of the name server shown by the
dig utility output (johndoe.com): provider should edit or remove PTR record for 203.0.113.2 that is stored on their side.