I have used Diagram for years and all of a sudden the hyperlinks have stopped generating on the server side HTML rendered. It was working till last night and then stopped.
Our Aspose.Diagram licence expired earlier in the month so not sure if that is related. We haven’t changed any code and it was all working fine a month after licence expiry.
We’re going absolutely nuts trying to figure it out - server reboots etc etc.
The HTML generated content is no omitting the HREF links totally out of the blue.
Help would be appreciated 
Andrew Hudson (in the UK)
Hi Andrew,
Thank you for contacting support. Did you upgrade the Aspose.Diagram for .NET API version in your environment? If so, then it may due to this. Kindly make sure that the Aspose.Diagram for .NET API release date is less than the license expiry date. Please share more details like, which Aspose.Diagram for .NET API version you are using, license expiry date, code and a sample Visio drawing which you are converting to the HTML format. We will investigate and share our findings with you. Your response is awaited.