iPad controlling MacBook Pro won't zoom

Hi all Community members

Started using TeamViewer very recently and absolutely delighted with it. However, recently hit a snag when remotely accessing my laptop from my iPad. My iPad screen won't zoom now.

It did so previously and works fine on my iPhone, except for its rather small screen even though it does zoom.

It could be something I have done inadvertently with the settings but I don't know what.

Any suggestions will be very gratefully received

Thanks

M