Confluence has bugs that can break the Confluence content indexes when you upgrade your Confluence Server.
Apps that find resources on other pages, like the MultiExcerpt Include macro or the Easy Forms Report macro, will break if the Confluence content indexes are broken.
The symptom will be that a MultiExcerpt Include or a Easy Forms Report reports an error that it cannot find the page it is looking for.
If you are certain that the target page exists then a quick fix could be to edit/save that page to rebuild the index for that page. However, if you suspect that your Confluence Content indexes are broken after you have upgrade your Confluence Server then you should rebuild the indexes. See the Atlassian document: How to Rebuild the Content Indexes From Scratch on Confluence Server