So it�s not possible to send emails using Dynamics 365 for phones application due to an error message saying "The entity for this client is read only".

This is due to the fact that the feature to send emails using Dynamics 365 Mobile App is set as read only by default.

I have had a case with the Dynamics team regarding this as i think it�s really strange that you can�t send emails to specific customers in the app.
The guys i talked to in the Dynamics team also thought that it�s quite strange. If you have a sales team which mostly are on the run - this is a must have feature.

I don�t see why you shouldn�t be able to do this?

Please make this work.
Thanks!