With a document open in TerraGo Toolbar or TerraGo Composer, under the TerraGo menu entry, select GeoPDF File Properties to bring up its dialog. On the TerraGo tab, you will see a GeoPDF? entry, displaying Yes or No.
If the entry is No, then the file is not a GeoPDF document and TerraGo Toolbar will not work by design. However, you can still investigate the georegistration metadata of the geospatial document using the tree to the left regardless of PDF origin.
If the entry is Yes, then the file is a GeoPDF document. If, however, TerraGo Toolbar still doesn’t seem to work, verify that the Tampered? field says No. If it says Yes, then something has corrupted the georegistration metadata or otherwise made unauthorized changes to the document. Attempting to remove the watermark from a GeoPDF document made by TerraGo software in evaluation mode can cause the document to be marked as tampered. Finally, if GeoPDF? is Yes, and Tampered? is No?, Open TerraGo Preferences under Edit->Preferences->TerraGo… On the Coordinate Display tab, verify that “Multi-Coordinate GeoDisplay” is checked.