cannot reply to received messages

cannot reply to received messages

When I first began using zoho, all worked well other than the fact that any messages composed defaulted to the smallest font, a bit of a hassle but easily overcome.

Then suddenly the system didn't seem to work at all and it seemed to change format.  Then I found that I could at least see my emails by clicking "all messages".

But since that time, i cannot reply to a message.  Nothing happens at all when I click "reply".  The only way I can do a standard reply is to copy the received message, go to contacts and start a new message, copying the original message and formatting it all myself... this is a nuisance.  Am I doing something wrong?  Any other mail system formats the new message simply by clicking "reply".  I don't want to lose my zoho address, so what can I do to make this work?