I’m getting VBA OLE ERROR 800A03EC error when using the VBA compiler

Make sure that “Trust access to the VBA project object model” option is enabled in Excel.

See this page about how you can access this option:

https://support.office.com/en-nz/article/Enable-or-disable-macros-in-Office-documents-7b4fdd2e-174f-47e2-9611-9efe4f860b12