It might be helpful to any fellow-user wishing to respond to your post if you were to include rather more detail! This post shows the sort of level of information that is requested.
However, the answer to your "question" is almost certainly that the Trial version is deliberately limited in the length and type of Export that it will allow. Once purchased and registered, all such restrictions are removed. If you do decide to purchase the software the recommendation here is always to buy at least the Plus and preferably the Premium version