I was having a very similar error, but I contacted someone from Noble Image (a company we used to help us setup the site), and she was able to fix it for me.
It’s because I had updated to a newer version of WordPress (the core was updated) and it threw off plugins.
I’m having this problem too, and the reply above makes no sense to me at all. I can’t login to our webpage at all. Header errors
I’m having this problem too! I didn’t add any plugins though, and I cannot get onto our webpage at all
