I was having the same issue and I tried basically everything mentioned here too, without any immediate success.
Like others also mentioned, in the quest for what the problem was I ultimately narrowed it down to (guessing) that the valve actuator which opens the rubber drip outlet must be faulty, since it flows fine when manually pushing the rubber nozzle on the cartridge.
but when the form3 is supposed to be “filling up the tank” there is not a drop to hit the floor for a few hours until the printer finally enters time out error.
Days prior to this, the printer was giving notifications about no cartridge detected while there is a full one in the machine.
Anyways In my case though, getting frustrated with the hours of my day wasted I kept trying and checking by reinstalling the cartridge over and over and in the process I ended up “dunking” the cartridge down into the slot of the form3 with increasing amount of force, which ultimately led to a perfectly functional printer and the problem never returned afterwards.
Maybe it’s a bug where the droplet actuator somehow gets locked up and needs a thud to unjam? Just a thought