This error comes back time-to-time, especially after a Joomla site is moved from one server to another. The symptoms are simple - but frightening. You try to login to the administrator interface as usual, with your well known credentials, and the login box is reloading whitouth any kind of error message and withouth letting you in. No errors in browser console, no error in the logs, and no errors even if you turn the error reporting to maximum or the Joomla debug on. You can try even the tricks described elsewhere in this site to change your admin password - that won't help.

Why? Because the cause(s) - yeah, there can be multiple causes - are different from having bad credentials! Let's see what you can do about!

ATTENTION: these tricks are qualified as core hacks, so be careful: backup, wear your lucky hat, keep your finger crossed - and take any other security measures before you proceed - you can ruin your site easily with a wrong move.

Today I have faced a strange, never seen before error. I have worked on recovering a server with couple of old Joomla sites after a major crash, when one of sites ceased to "fly" again, and showed up nothing else but a white screen with this text:

Infinite loop detected in JError

After year of using myself the tip You Do Not Have Access to the Administrator Section of This Site successfully today I hit the wall.

I did one more stunt as the ones described above - but didn't helped.

But let's see first the failed hack - because that\s interesting too:

I was sure that ths is an error wich newer come back to me - was a relatively common one in early 2010-s, since dissappeared from my radar. Today one of my former students approached me with his problem. He took over a site running the latest Joomla, and when tried to change the blog list views to category blog views, as the siteowner requested, the respective pages ended up with a white PHP fatal error death screen.

Recently in more (usually cheap) hosts more of my clients reported a strange error, wich showed up recently, withouth notice.

The error message is like this:

1104 The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay

followed by the failing query.

Today I had to upgrade an old, Joomla 2.5.7 site to latest Joomla, everything went out fine until I had to do the first critical step - the upgrade from Joomla 2.5.28 to Joomla 3.51. Did I mentioned that server has PHP 5.6.25 withouth possibility to upgrade - at least not on short term?

OK, so, wasn't the best setup condition available, but usually this is not a dealbreaker.

And BUMM, I have seen an old "friend", a popup saying:

ERROR: Invalid login