Hi Marcus,
Thank you very much for your interest in Syncfusion Products.
We were unable to reproduce the issue from our end. We have created a sample and tested with dlls of version 9.2.0.18 in 3.5 framework. Setting horizontal page break using ws.HPageBreaks.Add(ws.Range["A51"]); will insert the page break at row 50 and setting vertical page break using ws.HPageBreaks.Add(ws.Range["A51"]); will insert the page break at column F. For your reference, we have attached the sample below. Could you please find the sample and let us know if this helps you?
Sample Link:
http://www.syncfusion.com/uploads/redirect.aspx?&team=support&file=SettingPageBreakSample1645289335.zipIf you still encounter any issue, it would be great if you could revert back with a simplified issue reproducing sample or the input template, which will help us to investigate further.
Please let us know if you need any further assistance.
Regards,
Pauline Bosco