From McIntosh website
https://www.mcintoshlabs.com/product...treamers/MS500
UPDATE: MS500 and the end of Adobe Flash
The web browser user interface for the MS500 utilizes Adobe Flash. As of December 31, 2020, Adobe is no longer supporting Flash Player and they will block Flash content from running in Flash Player beginning January 12, 2021. To allow MS500 users to continue using the MS500's web interface, we have worked with our partners at Autonomic to produce a new interface for the MS500 that does not rely on Flash. To minimize any disruptions in users accessing their MS500 via the web interface, we are releasing the current working version on January 11, 2021. This will be followed by a later version that includes the familiar McIntosh MediaBridge branding. To access the new interface, the latest firmware must be installed on your MS500. To install the new firmware:
Using a computer connected to the same network as the MS500, launch an internet web browser.
In the "URL-Address line" type in the IP Address Number of your MS500 and add "/config" to end of the address (for example: 192.1.168.130/config).
Select the Firmware Tab.
Select Update in the firmware Update Window.
Adobe ending support for Flash does not affect the free MediaBridge control app that is available for iPhone, iPad or Android devices, or the handheld remote control that is included with the MS500.