as noted in the EZD3 System Requirements,
the EZD3 plugin requires a 64-bit host that supports VST3, AU & AAX.
what version/edition of Samplitude Pro X are you using?
SYSTEM REQUIREMENTS.
18 GB free disk space (plus 18 GB for download).
64-bit Windows 7 or newer, 4 GB RAM (8 GB RAM or more recommended).
macOS 10.10 or higher, Intel or Apple silicon processor, 4 GB RAM (8 GB RAM or more recommended).
A 64-bit host (with support for VST 3, AU or AAX). Standalone is included.
