Unable to Export Composition using Media Encoder

Update After Effects and Adobe Media Encoder to the latest version, or make sure that both the applications are of the same version. For example, if you are using After Effects 2019, make sure to use Adobe Media Encoder 2019.

• Add the composition to Adobe Media Encoder from the After Effects Render Queue.
• Choose Composition > Add to Render Queue. From the Render Queue, click Queue in AME.

In Adobe Media Encoder, select Media Encoder CC > Preferences > General and turn off Enable Parallel Encoding.

• In Adobe Media Encoder, select Media Encoder CC > Preferences > General.
  
• Under Video Rendering, change the Renderer to Mercury Playback Engine Software Only, and click OK. 

Reset preferences for Adobe Media Encoder. Make sure that Adobe Media Encoder and After Effects are closed in your machine (while following the steps).

macOS

• Quit Adobe Media Encoder and After Effects.
• Open the Finder, hold Option, and click Go on the menu bar.
• Click Library and navigate to Preferences > Adobe.
• Rename the Adobe Media Encoder folder to Old_Adobe Media Encoder.
• Close the window and navigate to Documents > Adobe. Rename the Adobe Media Encoder folder to Old_Adobe Media Encoder.

Windows

• Open the Run dialog (Win+R) and type %appdata%.
• Open the Adobe folder, and rename the Adobe Media Encoder folder to Old_Adobe Media Encoder.
• Close the window and navigate to Documents > Adobe. Rename the Adobe Media Encoder folder to Old_Adobe Media Encoder.

Clean installation for Adobe Media Encoder. For more details on how to clean installation, see Use the Creative Cloud Cleaner Tool to solve installation problems.