Answer:
There could be many reasons, but probably the company reached its debt ceiling and is not able to borrow anymore (at acceptable conditions), due to low net cash flow relative to debt service, or low available collateral, or both.
Larger expansions or risky undertakings would also be more likely financed by equity - the expansion might require taking on more debt than the company is currently able to service, and the creditors are not sure if it will also bring sufficient additional EBITDA to service large debt. Similar thing with risky business proposals - it is more logical to finance them through equity, where investors share the hard-to-predict benefits as well as potential losses. If they were to be financed by debt, the loan should in theory carry very high interest to make up for the risk profile of the endeavor. Better to make it an equity investment.
Also, issuing equity improves your balance sheet and enables you to take on more debt. Having more equity could also mean cheaper debt (better interest rates). Debt is considered “senior” to equity, in theory losses should hit investors first and creditors later, so having a larger equity cushion means lower credit risk.
If the company suffered some hard times, they are already starved for cash and on top of that creditors would likely want to reduce their exposure - a perfect storm that could put the company out of business due to lack of liquidity, even when the business model is good in the long term (but who has a crystal ball, eh?). Raising more equity may be their only option.