Urgent Help Needed: Troubleshooting using Excel saved in Sharepoint as a dataset

Hi all,

A bit of context, I have published a PowerBI report and have shared it across to my team via Teams. For the report, I have been using an Excel file as the dataset. I have set it to autorefresh every day at midnight. So far, the auto refresh has been working perfectly for the past 2 months or so. However, today I got an email notification notifying me that the refresh failed. This was the error displayed:

Web.Contents failed to get contents from 'https://redactedhisonpurpose.sharepoint.com/sites/DealPipelineforDirectPE/_api/web/getfilebyserverrelativeurl('/sites/DealPipelineforDirectPE/Shared%20Documents/PE%20Direct%20Deal%20Pipeline.xlsx')/$value' (404): Not Found

I thought that it was weird, as it seems to me that the PowerBI service was not to able to find the file. I tried manually going to the url via a web browser, and was met with a 404: Not Found Error. I thought this was weird, as it has never ran into this kind of issue before. 

The next step in troubleshooting was me trying to replace the dataset manually. I went into the report via PowerBI desktop and attempted to change source for my dataset. I inserted a new sharepoint url (have made sure that the url can be found) and tried to change it, but I was met with this error

It says that it was not able to authenticate based on my credentials. I am positive that my Office365 email and password are absolutely correct. I am not sure why I am getting this error.

I appreciate any help in sorting this issue. Many thanks in advance!