我已经通过 Déjà Dup 备份工具在 Ubuntu 18.04 上启动了备份，但失败并出现以下错误：
Backup Failed InvalidBackendURL: missing // - relative paths not supported for scheme invalid: invalid://`
版本deja-dup是37.1-2：
$ sudo apt list -a deja-dup
Listing... Done
deja-dup/bionic-updates 37.1-2fakesync1ubuntu0.1 amd64
deja-dup/bionic 37.1-2fakesync1 amd64
我已将我的主目录标记为要保存的文件夹，并将垃圾、~/miniconda3 和 ~/Downloads 标记为忽略。我正在将备份保存到外部硬盘上。
我也看到这些错误：
Traceback (innermost last):
File "/usr/bin/duplicity", line 1555, in <module>
with_tempdir(main)
File "/usr/bin/duplicity", line 1541, in with_tempdir
fn()
File "/usr/bin/duplicity", line 1380, in main
action = commandline.ProcessCommandLine(sys.argv[1:])
File "/usr/lib/python2.7/dist-packages/duplicity/commandline.py", line 1135, in ProcessCommandLine
backup, local_pathname = set_backend(args[0], args[1])
File "/usr/lib/python2.7/dist-packages/duplicity/commandline.py", line 1010, in set_backend
globals.backend = backend.get_backend(bend)
File "/usr/lib/python2.7/dist-packages/duplicity/backend.py", line 223, in get_backend
obj = get_backend_object(url_string)
File "/usr/lib/python2.7/dist-packages/duplicity/backend.py", line 209, in get_backend_object
return factory(pu)
File "/usr/lib/python2.7/dist-packages/duplicity/backends/giobackend.py", line 97, in __init__
self.remote_file.make_directory_with_parents(None)
Error: g-io-error-quark: Error creating directory /media/james/passport: Permission denied (14)
以下是执行备份的磁盘的权限：
$ ll /media/james/passport
total 100
drwxr-xr-x 4 james james 32768 Dec 31 1969 ./
drwxr-x---+ 3 root root 4096 May 29 10:59 ../
drwxr-xr-x 3 james james 32768 May 29 10:59 scw/
drwxr-xr-x 5 james james 32768 May 29 10:48 .Trash-1000/
为什么我会收到上述错误？我该如何解决？提前感谢大家提出的任何建议。