Ubuntu – Android devices not recognized in Ubuntu 16.04

I'm trying to set up my app development environment and have hit a snag. When I connect an Android device to my laptop running Ubuntu 16.04, it is not recognized in any way. It starts charging, but I don't get any popups asking me to connect or mount it. This is happening with two different devices (Samsung Galaxy S8 Plus and Lenovo Yoga Book) and multiple USB cables.

When I run lsusb it does not show any Android devices. I have connected to every USB port on the laptop and none of them are working.

Bus 002 Device 003: ID 0a5c:21e1 Broadcom Corp. HP Portable SoftSailing
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 04f2:b270 Chicony Electronics Co., Ltd 
Bus 001 Device 003: ID 138a:003d Validity Sensors, Inc. VFS491
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I created an Android rules file with the following contents:

SUBSYSTEM=="usb", ATTRS{idVendor}=="0bb4", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="0502", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="12d1", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="1004", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="22b8", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="04e8", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="0fce", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="0489", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="18d1", SYMLINK+="android_adb", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="04e8", MODE="0666", GROUP="plugdev"dev

I've edited /etc/fuse.conf

# /etc/fuse.conf - Configuration file for Filesystem in Userspace (FUSE)

# Set the maximum number of FUSE mounts allowed to non-root users.
# The default is 1000.
#mount_max = 1000

# Allow non-root users to specify the allow_other or allow_root mount options.
user_allow_other

I've turned on developer options and enabled USB debugging on both. My user is part of the plugdev user group.

adb devices is empty.

I've already rebooted a few times.

These are all of the steps I have found when searching online. Nothing has resolved the issue so far.

I don't know what the next step is. Does anyone have a suggestion?

Edit to Add

When viewing the system logs, if I connect a different USB device, such as a headset, I see a lot of activity in the system log. When I connect an Android device, nothing happens in the logs. It's like it just doesn't detect anything at all. I don't understand this.

Edit to Add 2

Okay, so I figured out what was wrong and it was really silly. I forgot that I had a charging case on my phone. Apparently you can transfer data through the pass-through port on the charging case. After removing the case, I can connect my Samsung phone. The other two tablets still don't connect, but they use a different USB cable, so maybe there is an issue with that cable. That was really frustrating!