File/Share/Email/Send as Attachment uses thundebird

Hi,

I have following configuration :

Windows 10 Enterprise 1903.

Installed office 365

Installed thunderbird

Set Outlook as app default

anyway when from Excel i do 

File/Share/Email/Send as Attachment

thunderbird is opened instead of Outlook.

Any suggestion ?

The same problem, if i right click on a file and choose send to>mail

Thanks in advance

Fabrizio