Unable to Insert Images in Replies

As of today I am unable to use the Insert Image button on the toolbar of the WYSIWYG editor to add images to my replies. After I browse to the .png file and click OK I see the error "Failed to upload image! Please try again" in the  Add Image pop-up window. The same error message appears if I try to drag and drop the .png image file. See a screenshot of the error at https://ibb.co/CJvCxNr.  

I can copy and paste a .png file into the WYSIWYG editor and this appears to work while the reply is still in preview, but after the reply is posted the image disappears.
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Dell Inspiron 15 5584 * 64-bit Win 10 Pro v22H2 build 19045.5011 * Firefox v131.0.3 * Microsoft Defender v4.18.24080.9-1.1.24080.9 * Malwarebytes Premium v5.1.11.133-1.0.5048 * Macrium Reflect Free v8.0.7783 * Dell Update for Windows Universal v5.4.0 * My Dell v2.2.6.0 * Fusion Service 2.2.14.0