Post.php lead to blank screens I have many PHP warnings and errors

Can you reproduce the issue — where saving a post leads to a blank screen — with ALL plugins deactivated AND the default Twenty Sixteen theme? If so, I would suggest, on the same host, installing a non-multisite version of WordPress and trying to reproduce the issue again. If you cannot reproduce it then I would set that site up as a multisite and try to reproduce again.

If, on the other hand, after deactivating ALL your plugins AND switching back to the default theme allows you to properly save posts as well as not get all the error messages with debug on, then I would switch back to your Frank theme. If, after switching to Frank (LOL), you are able to reproduce any of the issues then I would contact Frank’s author and let them know about the issues you found.

Oh, and if Frank does misbehave on your multisite, without any plugins being activated, then I would try Frank on a freshly installed NON-WordPress multisite on the same host.

Hope this helps!

Did you edit the functions.php? Or another php file? It could be caused by having to much white space between end of function and closing php tags or beginning php tags

<?php

Too much white space
Start function {

}

Too much white space
?>

I hope this will be the cause

@randy I can’t make many installations to test.
I’ve tested already with Twenty Sixteen, it does not work, the problem seem to be linked to the folder “plugins” and not to the activation of the theme. And on front-end I have no problem : the pages are served, cached etc, my site works normally. Only the back-end has problems.

@Djenci Yes I have made many editions in many php files recently, and I also tested and activated many plugins. I was trying to optimize the speed of my site. It worked well, I get notes like 96, 98… and a broken admin ?? was worth the effort…
So, I’ll check again but… as I said, I’ve reinstalled WP already, by 2 methods (from the network’s admin and by FTP), so files like functions.php are THE ORIGINAL WP core files, so there’s no white space bug there.

Now since my WP core files and my themes files are the originals, the mistake has to be somewhere else. But where?

I often had blank page issues with w3 total cache plugin. That’s why I completely did caching myself

As wel as combining javascript, CSS and minified it

Does deactivating the plugins for caching solve the issue?

No it doesn’t. Deactivating ALL the plugins does not solve the problem. The only way the problem does not appear, is if I RENAME the folder “wp-content/plugins”.

Weird isn’t it?

If it would be one plugin causing the problem, it would be easy to solve. But here, it’s the existence of the folder “plugins” itself!

So you change the folder plugins to what name? plugin? Can you post ur url one time? Does it appear when you put cloudflare in developer mode?

This is nofollow here so don’t worrie about putting ur url

Update : the cause of problem 1 (blank screen when posting) was in the plugin Wordfence, no idea why, but I have to remove it from the “plugins” folder, then posting works again.

It’s really weird because nothing changed recently with Wordfence. There was no updates and I did change the code at all.

@Djenci: my url wouldn’t help, since the problem was in the admin or is in the error files. Nothing is visible.
And, I have a rule in CloudFlare to bypass the cache for all WP-admin files, so that could not be the cause. Only my public pages go through CloudFlare.

So, there are still all those errors in the logs, can someone help with that?

Update : no, actually problem 1 was not solved.I just thought it was.

I had deleted all the plugins from the folder “plugins”. Posting OK.
Then I put back the plugins 5 by 5. Posting OK, OK, OK.
Then I came to the 5 last. I put them 1 by 1, posting OK, until I came to Wordfence, then I couldn’t post any more. So I concluded Wordfence was the problem and I deleted it. Posting worked.

Then I activated the last plugins I had uploaded. I check whether I could post or not and: NO, it leads to white screen again.
Then I deleted the 5 last plugins, since posting worked until I uploaded them. But even back to the situation when it worked before, it doesn’t work now: posting leads to error.

it drives me mad. 2 days on this already !

Update : the problem with register_sidebar is solved. The “functions.php” of my theme forgot to give an idea to all the widget zones. I just had to add ‘id’=>’name’ and that was it.

If somebody meets the problem with the theme FRANK, the functions.php file should look like that in the part about sidebars:

function frank_widgets() {
	register_sidebar(
		array(
			'name'      	=> 'Sub Header',
			'id'      		=> 'widget-subheader',
			'before_widget' => '<div id="%1$s" class="widget %2$s four columns">',
			'after_widget'  => '</div>',
			'before_title'  => '<h3 class="widget-title">',
			'after_title'   => '</h3>',
		)
	);

Ok I think understand what caused the impossibility to post.

I had P3 plugin profiler activated on 1 of my subdomain sites. I had launched a test and P3 had crashed, thus I thought it had stopped, but now I think it didn’t: it continued trying to test the other plugins, consuming memory and leading other plugins to cause Fatal errors by lack of memory. That’s why I still had the problem when I believed all my plugins were deactivated: P3 was still activated on 1 subdomain!!

My provider has raised my memory limit to 96M instead of 64, so I could stop P3 profiler, and from that moment, I could save posts again all over my sites.

Now I think most of my problems are solved. thanks to those who stimulated the problem-solving!