We are using Exchange Defender to block spam and other emails that could cause potential issues on the network and everthing from ring central is being blocked. We whitelisted and trusted the site and still blocked. Contacted the vendor and they said it appears as though Ring Central is having DNS issues. It is effect all out fax confirmations. Here is the email from our vendor.
Please contact us about this issue.
It looks like ring central may be having DNS issues in serving requests. Unfortunately the whitelists rules that you created wouldn't apply in this case because SPF, DKIM and DMARC are policies set by the senders domain (in this case, ringcentral.com) and their policies dictate how to handle authorization failures (to prevent some external entity from sending spam as ringcentral.com)
Jul 23 08:41:06 inbound17 opendkim[1457]: 06NCf5WI040147: key retrieval failed (s=mail, d= ringcentral.com): ' mail._domainkey.ringcentral.com' query failed
Jul 23 08:41:06 inbound17 ExchangeDefender[40147]: 06NCf5WI040147: Milter insert (1): header: DKIM-Filter: OpenDKIM Filter v2.11.0 inbound17.exchangedefender.com 06NCf5WI040147
Jul 23 08:41:06 inbound17! opendmarc[17037]: 06NCf5WI040147: SPF(mailfrom): service@ringcentral.com tempfail
Jul 23 08:41:06 inbound17 ExchangeDefender[40147]: 06NCf5WI040147: Milter insert (1): header: Authentication-Results: inbound30.exchangedefender.com; spf=tempfail smtp.mailfrom=service@ringcentral.com
Jul 23 08:41:06 inbound17 opendmarc[17037]: 06NCf5WI040147: ringcentral.com fail
Please contact us about this issue.