James said

The Flash Player download options for Linux from https://get.adobe.com/flashplayer/ is perfectly safe. I prefer to install Flash by way of extracting libflashplayer.so from .tar.gz and placed into created plugins folder in /home/username/.mozilla/plugins/ Downside is you have to manually update however I can get new versions faster and have control.

Thankyou James. I'll try that solution. I accept the safety of such way.

Thank you for your screenshot. From it I can see that the Flash plugin is provided by the flashplugin-installer package. To file a bug against it in Lubuntu 17.10, more information is required:

• From your screenshot, Firefox shows an empty space instead of the video. It does not give an error message. Rather than saying "Firefox blocks the video", we can say "Firefox shows an empty space instead of the video and does not produce any error message". Is this correct?
• "I Tried to install version 28.0.0.137 of Flash Plugin but "Software" (Apt/Debian) does'nt permit." -- What error message does it show?
• What happens when you type "sudo apt install flashplugin-nonfree" in a Terminal?

I understand that gathering this information requires an attempt to install Flash from the package manager rather than from Adobe website like suggested by another helper here. This may be confusing. I apologize.  :-) Nevertheless if you have a chance to provide this information, Lubuntu 17.10 may be improved for other users.

To be clear, I confirm that both the "flashplugin-nonfree" package and the Flash Plugin from Adobe website are considered safe on this forum. If any of them does not work, this is is a bug.

Svetlana said

Thank you for your screenshot. From it I can see that the Flash plugin is provided by the flashplugin-installer package. To file a bug against it in Lubuntu 17.10, more information is required:

• From your screenshot, Firefox shows an empty space instead of the video. It does not give an error message. Rather than saying "Firefox blocks the video", we can say "Firefox shows an empty space instead of the video and does not produce any error message". Is this correct?
• "I Tried to install version 28.0.0.137 of Flash Plugin but "Software" (Apt/Debian) does'nt permit." -- What error message does it show?
• What happens when you type "sudo apt install flashplugin-nonfree" in a Terminal?

I understand that gathering this information requires an attempt to install Flash from the package manager rather than from Adobe website like suggested by another helper here. This may be confusing. I apologize.  :-) Nevertheless if you have a chance to provide this information, Lubuntu 17.10 may be improved for other users. To be clear, I confirm that both the "flashplugin-nonfree" package and the Flash Plugin from Adobe website are considered safe on this forum. If any of them does not work, this is is a bug.

Thanks very much. About the more information required, can say: 1- Yes, it is correct to say "Firefox shows an empty space instead of the video and does not produce any error message" 2- Apt/Debian on Lubuntu 17.10 says something like "no source/partner found for this package" 3- I disinstalled Lubuntu 17.10 so I cannot respond on this item about sudo etc It is right to improve Lubuntu 17.10. Lubuntu 16.04 works very well. Thank you again.