Can’t access dashboard after update to 4.8

I had the same problem, and it was resolved for me by deleting all cookies for my WordPress domain. Seems to work, but maybe the problem returns later.

I found that it must be a bug in wordpress that in some cases causes cookies to be sent to the client until the the client cuts the connection. In my case over 2060 and a half cookie was sent wrongly. 282968 bytes of only cookie data…

I believe users that has not logged in to the site won’t have this problems. However in my case all system memory was also used up, creating big problems. I’m not 100 % sure this is related, but the two problems correlated.

I found out that my problem was related to “iThemes Security”. With this plugin enabled all server memory is consumed after just one web request and the client get loads of cookie data. After disabling iThemes Security (from Edge) all works as before (in Chrome), except that some security settings I had done in iThemes Security now breaks stuff. Revert settings in iThemes Security before disabling might be smart. And before all this, maybe just deleting browser cookies can fix the issue.

Thanks. Might have been a server issue, as it seems to have resolved itself.

I’m getting the same issue. I actually think it’s a WP 4.8 issue rather than iThemes. It’s directly related to a specific cookie (wordpress_logged_in_[hash]). When I clear that cookie, the site will load.

This occurs on multiple sites I administrate and was only encountered after the 4.8 update.

I have iThemes Security active. I disabled it rather than removing the cookie and the site loads. So it looks like there is something going on with that definitely. They’ve been tracking a bug that might be related.

• This reply was modified 7 years, 5 months ago by aibrean.

So is iThemes aware of the issue and actively looking into it?

It’s happening for me too since the upgrade to 4.8. Mine happens every once in a while but not all the time. Clearing my cookies lets the site load for me also. I was afraid that all my site visitors were seeing this error but it sounds like it affects those who specifically log in (some of our customers do). This has been driving me nuts. I’m glad I found this thread. Thanks!

Yes they are. I submitted a ticket and provided them with my headers and cookie information. They said they are trying to get a fix out soon (they said today when I chatted yesterday).

Awesome. Thanks!!

Same problem here, just updated to 4.8 and now I can’t access my dashboard. I’ll try clearing the cookies thing. But I don’t even remember how to do that, so now I have to look that up.

Deleted all cookies related to my site, still can’t get to the dashboard. I hate this I have no idea what to do now. I guess next step is to figure out how to get back to the old version.

Is your site running iThemes Security?

No I’m not, sorry I forgot to include that. Not running any cache plugins either.

Then it actually could be a true WP bug. Are you able to access other sections of the site?

• This reply was modified 7 years, 5 months ago by aibrean.

I do have securi alert though and apparently it’s still working because I just got another email from it. But I’m not sure, can I just go to the server through ftp and delete that plugin entirely? Kind of scared to do anything now.
I backed up stuff yesterday and I think my hosts keeps some other backups that can be reverted to, I’ll have to see if they can do that.

yeah, it seems any page that you don’t have to log into to access are ok.