I can confirm described behavior with Firefox 74.0 and Windows 10 - this is a huge productivity loss for me. The error seems to be related to the new Firefox version 74.0, which has been released a couple of days ago.
After dragging a hyperlink to Evernote, it will hang up Firefox completely (in addition to Evernote itself), until you manually kill the Evernote process via Task manager!
I have been using the same Evernote version 6.24.x, but with the change from FF 73.0.1 to 74.0, the hang up became apparent. Before, it was already noticeable with Firefox Developer Edition. Cannot remember the exact Evernote version, as I updated in the meanwhile, though it shouldn't matter.
Also tested with chromium browser , which works, so this is another point in favor of an incompatibility between FF and EN.