When you work with the Typo3 backend, you should use https, as you probably have to enter a password. Typo3 offers a flag to redirect backend traffic always to https. You can set it within settings/backend and checking lockSSL. Trouble comes when there is no ssl. Your connections to the backend will be broken from then on. Too many redirects, and, by the way, clearing your cookies won't help.
- It is valuable to have ftp access. Get the file LocalConfiguration.php from the typo3conf directory.
- Use your favorite editor to change to search for lockSSL and change the line to read
'lockSSL' => false,
instead of true. Save the file.
- Use ftp to transfer the file back to your server.
- Log in to your backend and strive to get https working.
On several occasions I had linked my pages, but the links did not work. The problems fell into two catagories:
- Page not found (error 404).
- Internal server error (error 500).
Sometimes – I don't know what I had done wrong – while working in the backend, Typo3 told me with a blue message that it had created redirects. These redirects where the cause of 404 errors. Having understood that, it was quite easy to delete these redirects in the backend, and anything was fine. again.
I had a perfectly working site at home and copied it to a server, and every link was broke (error 500). I re-linked pages, but that did not help. I almost was in desparation and thought about setting up the system completely again, until I found the cause of the problem: Instead of the carefully crafted Typo3-specific .htaccess file within the document root of the web server, there was another one that only kept PHP limits, probably written by the provider's configuration tool. So all rewrites had failed. Restoring the original .htaccess file and prepending the PHP limits did help.
You can improve security by having Typo3 send you an email whenever somebody fiddles with your backend. This is quite helpful, I thought. So I went to Settings/Configure installation-wide options, then backend configuration and edited [BE][warning_email_addr]. Chrome suggested my email address, I was pleased and accepted it. When I saved the config, Typo3 informed me that I had also set the compression level to 75177 (zip number of Pforzheim). This was not what I wanted. So I opened the config again and replaced the 75177 by the number 5 as suggested. Then I logged out. Trying to log in again, Typo3 was absolutely broken. Some checking showed that the installation-wide options get saved within LocalConfiguration.php. So I downloaded this file with my ftp client, deleted the line with the compression option and uploaded it again. Phew. Seems you have to leave the compression levele empty.