I have encounter this issue last two months, where our client reported that they link sent by SharePoint is not accessible. We have spent many hours until we advise to the client to avoid white space in the filename or folder. Fortunately, the client could accept our explanation that there might be limitation to the SharePoint just as we see limitation in URL format.
This month, Microsoft releases KB4011642 (January 2018 patches) – https://support.microsoft.com/en-us/help/4011642. It fixes the issue – so now you can create a folder or filename what contains white space and share the links without issue. The patch descriptions says:
When you upload a document or a folder and then share it to other users by selecting Share > Shared With > Email Everyone, the recipients receive an email message that has a broken link if the document or folder has a white space in the file name.
Yes, I confirmed the scenario is now fixed. Thanks Microsoft!