We began having issues when sending text messages to our contractors via vtext.com and vzwpix.com. Here is an example of the log entries from the SMTP conversation on our server:
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: Attempting to Connect: Host vrz-sms.mx.a.cloudfilter.net, Port 25, SSL Port 0, Connecting Domain server.wethinkit.net
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: Connection successful
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 220 vrz-ibgw-6003a.ext.cloudfilter.net cmsmtp ESMTP server ready
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: CommandEHLO: EHLO server.wethinkit.net
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 250-vrz-ibgw-6003a.ext.cloudfilter.net hello [68.66.193.88], pleased to meet you
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 250-SIZE 30000000
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 250-ENHANCEDSTATUSCODES
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 250-8BITMIME
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 250-STARTTLS
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 250 OK
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: SMTP Authentication is not required by local server. Username: -blank-
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: Attempting to SubmitMessage:
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: CommandMAIL: MAIL FROM:<[email address removed per the Verizon Terms of Service]> SIZE=2372
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 250 2.1.0 <[email address removed per the Verizon Terms of Service]> sender ok
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: CommandRCPT: RCPT TO:<[email address removed per the Verizon Terms of Service]>
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 250 2.1.5 <[email address removed per the Verizon Terms of Service]> recipient ok
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: CommandDATA: DATA
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 354 OK
07/25/2023 09:08:22 AM [03170:00015-00007F62352CD700] SMTPClient: Data Send Succeeded 1083 bytes
07/25/2023 09:08:23 AM [03170:00015-00007F62352CD700] SMTPClient: ReceiveResponse: 552 5.2.0 xx.xx.xx.xx blocked AUP#BL
07/25/2023 09:08:23 AM [03170:00015-00007F62352CD700] SMTPClient: CommandRSET:
07/25/2023 09:08:23 AM [03170:00015-00007F62352CD700] SMTPClient: Attempting to Disconnect:
07/25/2023 09:08:23 AM [03170:00015-00007F62352CD700] SMTPClient: CommandQUIT:
07/25/2023 09:08:23 AM [03170:00015-00007F62352CD700] SMTPClient: Connection terminated with status: 2562
07/25/2023 09:08:23 AM Router: No messages transferred to VTEXT.COM (host vrz-sms.mx.a.cloudfilter.net) via SMTP
We've checked our server IP address on all blacklists that we know of and are not listed anywhere. Is it possible we are on an internal Verizon blacklist? We've not had any issues with this until yesterday afternoon.
Please let me know how we can get this issues resolved as we use this extensively to communicate with our contractors.