First of all, when you write an email from your smartphone, be aware that the signature is not displayed but is automatically affixed when the email is sent.
If your recipients have not received your signed email, you should check the following points:
Make sure that the user concerned is present on the administration platform with an active signature.
2. Check that you have not set filters on a user group or domain name, for example, when activating the SMTP connector.
If despite these checks the issue persists, do not hesitate to contact us on the online chat or by email at email@example.com