From what I read cost over runs in solar farms in Qld has done the damage
While that might be the straw that broke the camel's back, I doubt that it is the cause of the collapse into administration.
The original ABC article notes that they took a $57 million writedown on two solar farms. They then raised $100 million from investors in August 2018. Audited statements to the ASX then stated that they were sitting on $140 million in cash. An AGM in October with no flags. A month later the company has gone into administration.
There is more to that story than cost over runs on solar farms.