[Tim Wood]

Does the From address of the mail from your phone match one of the addresses listed in the authorized addresses? It should either entirely match or it should match after stripping of the "Real Name <" prefix and ">..." suffix.

If you have any doubt; you could add a custom address in that list with exactly the text of the From: line in the mail message.

If this doesn't help; could you use Send Feedback and submit a screen shot of the mail rule in Mail (select 'Send to OmniFocus' in mail and edit it to pop up the sheet) and the mail you are sending? This may help us identify what's going wrong.