Overview
I encountered a bug where clicking Browse in Archivematica did not allow me to view folders or files. Here I introduce the cause and solution.
/transfer/

Symptom
/administration/storage/
Error retrieving locations: is the storage server running? Please contact an administrator.

Accessing the following returned this JSON:
/transfer/locations/
{
"message": "Error retrieving source directories",
"status": "Failure"
}
Solution
Accessing the following showed that the Storage Service was inaccessible.
/administration/general/

After correcting the Storage Service URL, the error was resolved.
Summary
I hope this serves as a useful reference for anyone experiencing the same issue.