Browse Error - Failure to Browse 'foldername'. The directory is invalid
Backup Error - 0xe000fe09 - The directory is invalid

It was seen that if the file in the folder started with a space or opening bracket ( , then the directory could not be browsed. The files or folder with some special characters failed the browse and backup.
This Issue is resolved in Backup Exec 21
Workaround -
To browse and backup successfully remove the space or opening brackets of all files in that folder. Rename these files which have a special character in front.
Note: If BE is installed on windows 2016 or earlier , the same shared folder on which the error was seen can be browsed and backed up.This Issue is seen when BE is installed on windows 2019