Cannot open excel file

Good Day

I have a .excel file saved to my MacBook and I have opened it in an attempt to edit and save a duplicate as I am just modifying dates and activities. When I attempt to 'save as' I am notified that I do not have permission to save to this location (despite the location). I then duplicated the document manually and made an edit and then got the same message. I then proceeded to open the original and got the message 'Sorry, we couldn’t find /Users/joshuavanniekerk/Library/Mobile Documents/com~apple~CloudDocs/'. I am not sure exactly what is going on as I have been able to use this method on multiple other .excel files and make duplicates or edits and then 'save as' to create a new modified version. I have tried moving the file to a new location or to my homepage, but the issue persists. I now cannot edit the original document and I cannot make another as the format I designed is very time consuming and specific. I know this is a Mac issue as I do not have this same issue with my windows PC.