After I upgraded version to 16.10.14, there have been several issues with diagrams,
like this error, but when i open the link the diagram shows.
Hello. I mostly sure, you’re referring to XWiki version and not Diagram extension that latest version is 1.3.
If your question is about contrib version of extension, than for first screen it’s worth initially to check whether original diagram page has both attachment (png and svg format). And for the second unknown error to make sure that browser cache is cleaned or at least to try edit diagram in private tab.
Unless, you’re referring to purchased extension, than community forum isn’t the best place to ask for a help, such extension is covered by license and includes a support contract for professional help from XWiki SAS.
BR,
Nikita
