English Translation
We must be more active to succeed in business.
Sounds unnatural a bit. Replace 活動的 with 積極的（せっきょくてき）.
The antonym of 積極的 is 消極的（しょうきょくてき）, which means that the company is always passively waiting for prospective customers coming in. So, 積極的 means the company proactively reaches out prospective customers and makes proposals to them.
活動的にならなければならない, on the other hand, implies that the marketing strategy of the company per se is okay, but the frequency of promotion is not enough. We don’t usually use 活動的 and 事業の成功 (business success) in the same sentence.