There is no specific limitation on the number of rows or data (by design). The Visma.net Financials driver reflects the metadata of Visma.net closely.
It might be that another table (API) is better suited or that Visma.net discontinued the functionality.
As a first step, it is recommended to find a record that is expected to be found in there with screenshot and provide that to Visma.net Financials Support with the question whether the related API should return it. And if not, what alternative API should return it.
The list of actual API access can also be found in the screen “Session I/Os” or the data dictionary view SessionIOs@DataDictionary.
In case Visma.net Support indicates that this is the right API and that the screenshot data should be in it, we can assist you on basis of a short consult. In case the omission is due to a bug in the Invantive UniversalSQL-driver for Visma.net Financials the short consult will not be charged.