webmail - send to address keeps disappearing

webmail - send to address keeps disappearing

In zoho webmail, when I try to compose an email to send, the send to address keeps disappearing when I tab out of the field.

Even if I don't tab out of the field, if I just click the Send button - the send to address disappears.

I keep getting the error message that I need to enter a send to address.

Not good - help please !