I'm guessing you are using the H910 Native plug-in (not the UAD plug-in).
Can you confirm you have the latest version of H910 (https://www.eventideaudio.com/support/product/8511/installers) and iLok License Manager (www.ilok.com)? What is your iLok account name?
You could also try the following steps:
- Make sure the plug-in is activated in the iLok License Manager.
- Close your DAW, and delete the following files:
- AAX: Mac HD/Library/Application Support/Avid/Audio/Plug-ins/Eventide/<plugin name>.aaxplugin
- VST: Mac HD/Library/Audio/Plug-ins/VST/Eventide/<plugin name>.vst
- AU: Mac HD/Library/Audio/Plug-ins/Components/<plugin name>.component
- Presets: ~/Documents/Eventide/<Plugin Name>/ (whole folder)
- Open your DAW and rescan you plug-ins, and then shut your DAW again.
- Reinstall your plug-in
- Reopen your DAW, and if necessary, rescan your plug-ins.
Let me know if you still have issues.