Outlook new mail format options grayed out

I am using MS 365 for business premium.
All of a sudden all of my text format options (font type, size etc. are grayed out when composing a new email despite the fact that html is selected as the format. This is the case when working on or offline. The mail option is set to HTMl and the format in the ribbon states HTML.
Is anyone else experiencing this and/or what can I do about it?