Plesk Installer web interface is stuck in an attempt to install/remove any Plesk component

Applicable to:

Ubuntu 18.04 is used.
Unable to install/remove any Plesk component via Plesk > Tools & Settings > Updates & Upgrades > Add/Remove components because the operation is stuck on the following step:

CONFIG_TEXT: All patches were applied
Refreshing the page gives the next error:

CONFIG_TEXT: ERR_CONNECTION_TIMED_OUT
The /var/log/plesk/install/autoinstaller3.log file informs that the installation was completed successfully:

CONFIG_TEXT: All patches were applied.
Patches were installed successfully.
The changes were applied successfully.

Product issue:

#PPPM-10191 "Autoinstaller Web UI stuck after component remove on Ubuntu 18.04"
Fixed in:
- Plesk Obsidian 04 June 2019 (fixed as PPP-41148)

Please consider updating your server:

If update is not possible for some reason you may try the following

temporary solution

As a workaround add/remove components via Command Line Interface (CLI):

Connect to the server via SSH.
Launch Plesk Installer:

# plesk installer

Note: If the command below is completed with the next output:

BUSY: Update operation was locked by another update process

Follow steps from this article.
Follow the instructions on the screen and install/remove the required component.