I installed 2.11.2 b ut it is showing no visits (no replies)

Hi

On Tuesday 24th February, I installed Piwik and it showed vistor numbers
very nicely.
But on Sunday 1st march these dropped to zero.
( I did an piwik update after 24th feb)

ecommerce conversion were also showing up
But now i am getting no data.

Can you suggest what i could try?

thanks
art