Hotpoint Mistral Frisge freezer triiping out the electrics- how can I fix ?

I bought a 2nd hand Mistral fridge freezer for the shed as an overflow. It arrived, we plugged it in and was shown how it works. It worked for 24 hours and then tripped out. The electrics in the shed are connected to the mains of the house, where we have a circuit breaker on the switch. I can plug my lawn mower and strimmer into the plug socket and it works perfectly- why does the addition of the fridge freezer trip it out ? I have a party to plan for next week and can't chill or freeze anything. Can anybody help and suggest a way to stop it ? I bought a monster power cable but that doesn't work either- I'm starting to loose the plot. Thank you.