Links Won't Work in Draft Compilation Box

I’ve been working on a draft for a while; all was good until recently.

I cannot now post or enter a link into the draft, the link does not post into the highlighted text that I want linked; any my cursor defaults to the top word of the blog draft. The cursor issue also happens randomly at times and defaults to the top/beginning word of the draft.

Help please, I can’t enter links or proceed?