In SM 9.3 KM attachment tab pasted txt attachment
then previewd the document -> and selected link button in the problem tab -> given link name -> next in the linking wizard attachment -> the attachment file name not found and attachment linking is not established
It seems you face the issue that links to an attachment inside a Knowledge Document fails and users experience "page not found", right?
If so, try to replace the SM attachment link type with standard HTML link type.
Please let us know then if this suggestion resolves your issue.