(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?
(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.
Under Common Law, failing to make progress on a project is generally not a basis for the client establishing a claim for damages. LDs are a reasonable pre-estimate of the damage suffered by the client for the late delivery of a project. However, if the milestone is a staged handover of part of the project, then LDs can certainly be applied.
Example:
Milestone 1 - complete piling under wharf. LDs cannot be applied, the only work following on is the contractor completing the wharf deck.
Milestone 2 - Hand over container berth 1 for commissioning (project involves several berths). LDs can apply the handover allows the client to start work towards earning revenue.
Civil Law is a bit different, it allows the partie to a contract to pre-set damages for failing to achieve a contractual objective.
For more on LDs see: https://mosaicprojects.com.au/PMKI-ITC-020.php#Process1