This is Unofficial Patch 1.5.6+ caused by the new option: "DISABLE Crowns System and Leaders". This problem won't be present if you don't use the mentioned option.
The recorded playback file (.e2s) doesn't contain the information about the state of "Disable Crowns System" option, so in the playback file crowns are enabled by default. It causes a bug where game hangs or crashes when you're watching recording. Unfortunately, it's impossible to create any online playback-converter which would fix this problem, because EE2 verifies validation of the playback file in some strange way. If you like to watch the games you play you should not use this option in the future.
You can bypass this bug, by modifying a fixed address in EE2 process memory, but it's complicated:
1. Download and start program HXD as Administrator: https://mh-nexus.de/en/downloads.php?product=HxD
2. In EE2 or EE2: AOS Load the playback file you want to watch, pause it and minimize the game.
3. In the HXD window click on the: "Extras" -> "Open RAM...". Find "EE2.exe" or "EE2X.exe" on the list. There should be 2x EE2.exe or EE2X.exe processess. One of them is the Launcher process, so you need to select the right one (select a different process if you fail for the first time).
4. In the window which appear you will see a hex view of the game process. Click: CTRL + G, and paste HEX Offset (copy the bold part):
- for Empire Earth II (EE2.exe):
- for Empire Earth II: The Art of Supremacy (EE2X.exe):
5. Type "01" (without quotes) using your keyboard, to overwrite "00" at that position.
6. Click CTRL + S and "YES" when you see the "Save anyway?" warning.
7. Done! Your playback should work fine with disabled crowns system. You have to repeat these steps EVERY time you load a playback file where crowns system was disabled.