I cannot even install it, browser says add-on is damaged

[FerryA1]

OS: macOS 10.14.6 Mojave Browser: Firefox v115.2.0esr

When I try to install it, a red warning shows up telling add-on is damaged and cannot be installed. The exact text is:

"The installation was aborted because the plug-in seems to be corrupted." (translated from Spanish) Find attached a capture.

Saluditos,

Ferrán.