imap impossible to enable ; free personal email account

hello,
i've juste created a free personal email account on zoho
when i go to settings, i enable imap, it says "your changed updated successfully".
then i go back to mail view, then i go back to settings and the imap is disabled.
so i don't manage to keep it enabled, and my thunderbird doesn't manage to connect.

any way out ? or is it a limiation of the free personal mail accoun ? no imap ?

thank you in advance

best regards

E.Rémond