Hi,
A picture of a fail print can help to understand what's wrong.
Cheap kits are made cheap, obvioulsy.
It's probably a connection problem. Check again connexions.
A wire is mabe cutted somewhere.
Even if Dupont connectors are mostly the encountered issues,
it's maybe not only about connectors.
If you glued the connectors, maybe you fixed the problem in place,
if any wire is not crimped in properly...
Check board's soldering too.
Last, check if motors/drivers don't get too hot,
and check the driver's output power.
Low powering can introcule loose steps.
It's wise to install a fan over the board for long prints.
++JM