Why are my replys to gmail accounts getting bounced?

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A message that you sent could not be delivered to one or more of its
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   jessica.murphy937@gmail.com
    host gmail-smtp-in.l.google.com [142.250.102.26]
    SMTP error from remote mail server after pipelined end of data:
    550-5.7.26 This mail is unauthenticated, which poses a security risk to the
    550-5.7.26 sender and Gmail users, and has been blocked. The sender must
    550-5.7.26 authenticate with at least one of SPF or DKIM. For this message,
    550-5.7.26 DKIM checks did not pass and SPF check for [symphonycs.com] did not
    550-5.7.26 pass with ip: [66.96.188.10]. The sender should visit
    550-5.7.26   https://support.google.com/mail/answer/81126#authentication for
    550 5.7.26 instructions on setting up authentication. ko7-20020a170907986700b00992bbbb019dsi7726435ejc.119 - gsmtp

Reporting-MTA: dns; bosmailout10.eigbox.net

Action: failed
Final-Recipient: rfc822; jessica.murphy937@gmail.com
Status: 5.0.0
Remote-MTA: dns; gmail-smtp-in.l.google.com
Remote-MTA: X-ip; [142.250.102.26]
X-Remote-MTA-smtp-greeting: X-str; 220 mx.google.com ESMTP ko7-20020a170907986700b00992bbbb019dsi7726435ejc.119 - gsmtp
X-Remote-MTA-helo-response: X-str; 250-mx.google.com at your service, [66.96.188.10]
X-Exim-Diagnostic: X-str; SMTP error from remote mail server after pipelined end of data: 550-5.7.26 This mail is unauthenticated, which poses a security risk to the\n550-5.7.26 sender and Gmail users, and has been blocked. The sender must\n550-5.7.26 authenticate with at least one of SPF or DKIM. For this message,\n550-5.7.26 DKIM checks did not pass and SPF check for [symphonycs.com] did not\n550-5.7.26 pass with ip: [66.96.188.10]. The sender should visit\n550-5.7.26   https://support.google.com/mail/answer/81126#authentication for\n550 5.7.26 instructions on setting up authentication. ko7-20020a170907986700b00992bbbb019dsi7726435ejc.119 - gsmtp
Diagnostic-Code: smtp; 550-5.7.26 This mail is unauthenticated, which poses a security risk to the
 550-5.7.26 sender and Gmail users, and has been blocked. The sender must
 550-5.7.26 authenticate with at least one of SPF or DKIM. For this message,
 550-5.7.26 DKIM checks did not pass and SPF check for [symphonycs.com] did not
 550-5.7.26 pass with ip: [66.96.188.10]. The sender should visit
 550-5.7.26   https://support.google.com/mail/answer/81126#authentication for
 550 5.7.26 instructions on setting up authentication. ko7-20020a170907986700b00992bbbb019dsi7726435ejc.119 - gsmtp

Return-path: < robert.mazarelli@symphonycs.com>
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Date: Tue, 08 Aug 2023 11:36:14 -0400
From: robert.mazarelli@symphonycs.com
To: Jessica Murphy < jessica.murphy937@gmail.com>
Subject: Re: Verified List of Libraries Contacts
In-Reply-To: < !&!AAAAAAAAAAAYAAAAAAAAAOq2Ob6K6J9Dkxq2Acbx8GXCgAAAEAAAADN73xYq529GszdmcbR/WEYBAAAAAA==@gmail.com>
References: < !&!AAAAAAAAAAAYAAAAAAAAAOq2Ob6K6J9Dkxq2Acbx8GXCgAAAEAAAADN73xYq529GszdmcbR/WEYBAAAAAA==@gmail.com>
Message-ID: < 4b5f5044edd0482ea02f42022f107f04@symphonycs.com>
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