kmail spellcheck doesn't work

Hello, gurus...:-)
I have kmail Version 5.3.3 (QtWebEngine) (KDE Frameworks 5.29.0, Qt 5.7.1
(built against 5.7.1), The xcb windowing system) in Fedora 25.
And spellcheck seems not to work: no erroneous words are red underlined,
only manual checking works.
I checked everything found in the Internet:
-aspell-en is installed,
- "View->Dictionary" is marked and is English US;
- "Options->Automatic Spellchecking" is marked in composer;
- Autocorrection in composer settings of kmail is enabled

Still, no red underlining in misspelled words...:-(
Please, any help!!!!

Leon