Possible issues with duplicate email addresses in [sys_user] tableSummary<!-- /*NS Branding Styles*/ --> .ns-kb-css-body-editor-container { p { font-size: 12pt; font-family: Lato; color: var(--now-color--text-primary, #000000); } span { font-size: 12pt; font-family: Lato; color: var(--now-color--text-primary, #000000); } h2 { font-size: 24pt; font-family: Lato; color: var(--now-color--text-primary, black); } h3 { font-size: 18pt; font-family: Lato; color: var(--now-color--text-primary, black); } h4 { font-size: 14pt; font-family: Lato; color: var(--now-color--text-primary, black); } a { font-size: 12pt; font-family: Lato; color: var(--now-color--link-primary, #00718F); } a:hover { font-size: 12pt; color: var(--now-color--link-primary, #024F69); } a:target { font-size: 12pt; color: var(--now-color--link-primary, #032D42); } a:visited { font-size: 12pt; color: var(--now-color--link-primary, #00718f); } ul { font-size: 12pt; font-family: Lato; } li { font-size: 12pt; font-family: Lato; } img { display: ; max-width: ; width: ; height: ; } } By default, the <email> field in the [sys_user] table is not set to be unique. This allows the same email address to be assigned to multiple users. Such duplication of email addresses is not a valid practice and can cause unpredictable behaviour(s) in the system. Hence, it is highly recommended to use a unique email address for each user when possible. Some of the possible issues that can occur from duplication of email address(es): Erratic behaviour of inbound email action(s) as the Email Reader scheduled job uses the first matched email address, which is not guaranteed to be the same every time if there are duplicate email addressesImpact on outbound notifications as multiple users will have the same email address in [cmn_notif_device] tableWhen the email address is defined as {nameID}, it can impact user logins if SSO has been configured on the instanceWhen you link your ServiceNow user account to a messaging application for Virtual Agent conversations, your messaging account is automatically linked to your ServiceNow account as long as the same email account is defined for both your messaging and ServiceNow accounts. Having duplicate email addresses can cause issues with Conversational Integrations for Slack, Microsoft Teams, and Workplace from Facebook when account auto-linking is enabled, which automatically links messaging users to their ServiceNow accounts using matching email addresses.Multiple user/contact records sharing the same email address across domains can cause cross-domain data to surface in domain-separated records Note: Possible issues have also been reported when using duplicate email addresses in child tables that extend [sys_user], including [customer_contact].