Triumph Sprint St 1050 Fuel Starved

I’m wondering if you could help. This bike was dry stored for 3 year. Took out for MOT and passed after a new rear tyre was fitted and a few other minor things. The bike was rode to the mot and back.
After this the bike was set away running on 5 litres of new fuel for 15mins on tickover to test temps on new antifreeze that was replaced. Left it over night and then the next day it started poorly for a few seconds and seemed to drop a cylinder then died and won’t even attempt to fire now. It feels like it’s ran out of fuel or being starved of it.

It turns over healthy but just won’t fire. Any help would be appreciated.

 

Thanks for the welcome. Much appreciated. I’ll check the plugs. The pump is kicking in so seems all ok that end.