I do have a large sequence diagram (20 participants, around 250 lines each with the corresponding note).
When I try to export the diagram as PNG, it gets truncated at the bottom (the plantuml server throws a forbidden error, so I cannot verify it). The PNG metadata has the complete diagram.
I am generating the sequence using the commando line.
When I export the diagram as SVG the sequence is rendered completely.
Further investigation, leaded me to remove both a legend on the top and a footer.... without those the sequence is rendered correctly.
Anyone with a similar problem?