Mark up will not work in preview

I opened a pages document in preview to edit with markup, it will not allow me to click any button to edit including Markup & signature, also I cannot click anything in the tools menu.

Usually this isn't an issue, though I have run into this problem for some files in the past and never found a solution.

The editing was unlocked for all on the pages document, don't know if that's relevant.

Hoping someone has a solution or at least reason why this is happening sometimes.