The email client sees only one long recipient address string if the 'To' field is populated via a script that contains semicolons to seperate email addressesDescriptionIf a script include populates the 'To' field with email addresses delimited with a semicolon, then the email client sees that as one long string which is interpreted as an invalid email address. The email does not pick up on the semicolon to separate the addresses, but treats them as only one recipient, as all the addresses joined together.Steps to Reproduce Open an Incident record2. Click on the email client. A script include auto populates the recipient address from the watch list with semicolon delimiters.3. Send the email.Check the status of the sent email. It is marked as send-ignored.WorkaroundThis is expected behaviour. The use of semicolons is only a UI choice (MS Outlook) to display separation of email addresses. In the script that auto populates the 'To' address field, use a comma as a delimiter instead of a semicolon. If you supply a comma separated list in the email client template script, the Email client will represent them as semicolons, but will allow typing semicolon if wanted. In MIME format, a semicolon is not an RFC-compliant email address separator (https://www.ietf.org/rfc/rfc2822.txt Section 3.4). In the backend lists elements are comma-delimited, so when an Email Client showing semicolons in the UI is sent in MIME format, the email headers TO, CC, BCC are converted back to RFC-compliant comma-separated to not get rejected.Related Problem: PRB1357468