I am having this exact same problem as of this past weekened.
I have noticed a few other symptoms:
If I try to add a new post in the admin panel, the form does not load.
If I try to go to the comments, there is no list appearing and the only filter selection that shows anything is the trash.
If I go to plugins, when I try to change the filter selection, I get another “Error 500 – Internal server error”
I even get the Error 500 when I try to deactivate the plugins, but only if I try to do it in bulk.
Something has changed without an action on my part, but I have no idea what it might be.
