I installed the Mobile Module filter, but when I send an email from my device the signature is just blank. Why? Modified on 2018-04-15 22:21:03 +0200 by Chris Jennings. You most likely sent out an email in plain text format and you have not created your default signature in plain text format. Quick 1-on-1 Demo | Ⓒ 2025 Xink Free 1-on-1