We used to be able to hyperlink to a phone number with an extension in marketing emails, but now it produces an unskippable error. You can hyperlink a phone number to text with the link tel:1234567890, but you were previously able to do extension as well (tel:1234567890,555) and it would go straight to the extension when you clicked the link.
Reached out to Support about this and they suggested I put this here, but this absolutely was a feature before that we somehow lost access to. I’d like it to come back, please. 