The default installation of Wireshark requires root privileges to run packet capturing. This is why I suggested below to run it as a privileged user. As @Warren Hill kindly pointed out this is not the recommended way to use Wireshark.
Please read How do I run WireShark, with root-privileges? and follow @Oli's answer on how to reconfigure Wireshark to be able to run as your own user.
To make the group membership changes effective (as stated in that answer) you'll need to log out or restart the system. If you do not want to do that right now for any reason, temporarily
login might help. (You'll have to specify your password twice: once for
sudo and once for
$ sudo login <your_user_name>
[sudo] password for <your_user_name>:
$ DISPLAY=:0.0 wireshark
Answer left below for reference:
Try to run Wireshark with root privileges:
According to the Wireshark Wiki:
Running Wireshark (or any other network capture/analyzer, for that
matter) on Linux needs root privileges. Therefore, you have to have
root privileges when starting Wireshark, else you can't capture data.
Please note that you don't have to login as root when starting your
computer, you can use su(1) or sudo(8) for that purpose.