MDM Android Devices - Gmail not allow to add attachments

[HC_MSGroup]

Hello,
I'm using Meraki's MDM for Android devices, namely Samsung A7/A8/A9 tablets. In terms of enrollment, we have not had any problems.
To use email, we are using the native GMAIL application and it works without any problems. The only issue detected is that when we compose a new email, 
it does not allow us to add attachments, nor does it even open the explorer. 
On the other hand, if we go through the file explorer, it is possible to share any file with GMAIL and then it create a new message with the attachment. 
Can anyone help? 
What its missing in MDM configuration?

thanks

[PaulF]

Have you used managed app config with GMAIL. This doesn't sound like a behaviour that can be achieved without managed app config

[HC_MSGroup]

Gmail is in the allowlist of system apps.
In the managed app config its only fields related to the email configuration. 

I've tried in the android app permissions allow all permissions without success. The issue remains the same. 

thanks for your answer