When uploading a document for a submission, an error message stating, "Please log in to access this resource" appears.
This error message is appearing because you've been signed out of Bonfire and this is preventing the file from uploading.
To resolve this issue and continue with your submission in Bonfire, you will want to click the Logout button located in the top right corner of your browser window.
A blue LOG IN / REGISTER button will appear in its place. Please click this to log in again.
Once you have logged in you can get back to your work in progress submission by clicking the Submissions button in the top black bar, then Actions -> View next to the opportunity.
From there you will be able to continue your submission and shouldn't receive an error message when uploading your document to Bonfire.