Recipient verification not working with LDAPS (Port 636)

Hi folks,

just noticied while scrolling thru the mail log, that a warning is thrown that no ldap bind was possible.

However, when adding and checking the authentication server all is fine and auth on 636 looking good.

Reverting to port 389 and the recipient verification check works again.

2022:05:25-11:50:39 utm exim-in[6104]: 2022-05-25 11:50:39 SMTP connection from [40.107.3.66]:13582 (TCP/IP connection count = 1)
2022:05:25-11:50:39 utm exim-in[23212]: 2022-05-25 11:50:39 H=mail-eopbgr30066.outbound.protection.outlook.com (EUR03-AM5-obe.outbound.protection.outlook.com) [40.107.3.66]:13582 Warning: Exception matched: Skipping greylisting for this message
2022:05:25-11:50:39 utm exim-in[23212]: 2022-05-25 11:50:39 H=mail-eopbgr30066.outbound.protection.outlook.com (EUR03-AM5-obe.outbound.protection.outlook.com) [40.107.3.66]:13582 Warning: example.com profile excludes greylisting: Skipping greylisting for this message
2022:05:25-11:50:40 utm exim-in[23212]: 2022-05-25 11:50:40 [40.107.3.66] F=<m.entase@sender.com> R=<sfbsdif@example.com> Verifying recipient address in Active Directory
2022:05:25-11:50:40 utm exim-in[23212]: 2022-05-25 11:50:40 H=mail-eopbgr30066.outbound.protection.outlook.com (EUR03-AM5-obe.outbound.protection.outlook.com) [40.107.3.66]:13582 Warning: ACL "warn" statement skipped: condition test deferred: failed to bind the LDAP connection to server ip-redacted:636 - ldap_bind() returned -1
2022:05:25-11:50:40 utm exim-in[23212]: 2022-05-25 11:50:40 1ntnf6-00062O-1F sasi reports probability: 0.087066, version: Antispam-Engine: 4.1.4, AntispamData: 2022.5.19.182717
2022:05:25-11:50:40 utm exim-in[23212]: 2022-05-25 11:50:40 1ntnf6-00062O-1F <= m.entase@sender.com H=mail-eopbgr30066.outbound.protection.outlook.com (EUR03-AM5-obe.outbound.protection.outlook.com) [40.107.3.66]:13582 P=esmtps X=TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256 CV=no S=10596 DKIM=sender.com id=AS8PR02MB7602B59DF7544689FD832D8DDDD69@AS8PR02MB7602.eurprd02.prod.outlook.com
2022:05:25-11:50:40 utm exim-in[23212]: 2022-05-25 11:50:40 SMTP connection from mail-eopbgr30066.outbound.protection.outlook.com (EUR03-AM5-obe.outbound.protection.outlook.com) [40.107.3.66]:13582 closed by QUIT
2022:05:25-11:50:42 utm smtpd[5990]: QMGR[5990]: 1ntnf6-00062O-1F moved to work queue
2022:05:25-11:50:50 utm smtpd[23255]: SCANNER[23255]: 1ntnfG-000635-Em <= m.entase@sender.com R=1ntnf6-00062O-1F P=INPUT S=746
2022:05:25-11:50:50 utm smtpd[23255]: SCANNER[23255]: id="1000" severity="info" sys="SecureMail" sub="smtp" name="email passed" srcip="40.107.3.66" from="m.entase@sender.com" to="sfbsdif@example.com" subject="test3ldap" queueid="1ntnfG-000635-Em" size="746"
2022:05:25-11:50:50 utm smtpd[23255]: SCANNER[23255]: 1ntnf6-00062O-1F => work R=SCANNER T=SCANNER
2022:05:25-11:50:50 utm smtpd[23255]: SCANNER[23255]: 1ntnf6-00062O-1F Completed
2022:05:25-11:50:50 utm exim-out[23258]: 2022-05-25 11:50:50 1ntnfG-000635-Em => sfbsdif@example.com P=<m.entase@sender.com> R=static_route_hostlist T=static_smtp H=ip-redacted [ip-redacted]:25 X=TLS1.2:ECDHE-RSA-AES256-SHA384:256 CV=no C="250 2.6.0 <AS8PR02MB7602B59DF7544689FD832D8DDDD69@AS8PR02MB7602.eurprd02.prod.outlook.com> [InternalId=200394584096895, Hostname=VSEX02.domain.local] 12060 bytes in 0.098, 119,325 KB/sec Queued mail for delivery"
2022:05:25-11:50:50 utm exim-out[23258]: 2022-05-25 11:50:50 1ntnfG-000635-Em Completed