Please help us help you and fill where relevant:
Your LimeSurvey version: 5.5.1+230103 (new install), 5.4.2+220921 (old install), self-hosted
Own server or LimeSurvey hosting: shared server at iris.mmnj.adv.br (new install) and questionarios.mmnj.adv.br (old install), hosted by 1984.is
ServerOS: Linux 4.19.0-16-amd64 Debian 4.19.181-1 (2021-03-19) x86_64
PHP 7.4.26
Web Server Software: Apache
Database driver: mysql
Driver version: mysqlnd 7.4.26
Database server version: 5.5.5-10.3.31-MariaDB-0+deb10u1-log
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Good morning, how are you? I apologize in advance for the bad English. I hope you can understand me.

I'm having an installation problem. I already have a LimeSurvey version 5.4.2 installed on a shared hosting accessible only via SFTP. It was working fine until I "broke" the encryption in an update (unfortunately I don't have the keys backed up, my bad.)

Having seen here on the forums that there is no way to recover compromised cryptographic keys, I decided to backup the surveys and the entire DB to install a new installation of LimeSurvey at the same server with a new subdomain (see above), preserving the previous version for future reference. 

I followed all the steps of the installation tutorial:
1) I used the latest version of LimeSurvey;
2) I saved the zip file on my local computer, and unpacked it locally;
3) Before uploading the new LimeSurvey to the server I configured FileZilla to use only binary mode
4) Also before uploading, I changed the permissions of the /tmp , /update and /application/config folders to 755. 
5) I upload everything normally. When I finished, I checked the permissions of /tmp , /update and /application/config again, and they were all kept at 755.

The problem started from here on: when I access iris.mmnj.adv.br/admin , I can only get an error 500 as a result. Meanwhile, the old 5.4.2 version is still accessible normally in the same server (see above).

I thought maybe the LimeSurvey compressed file had been corrupted during download. I downloaded it again, repeated all the above procedures, and got another 500 error. Meanwhile, the old 5.4.2 version is still accessible normally in the same server (see above).

I thought that maybe it was a problem with the latest version that I had installed at https:iris.mmnj.adv.br. I decided to download another file of version 5.4.2 to start the installation process again. Same result: error 500. Meanwhile, the old 5.4.2 version is still accessible normally in the same server (see above).

I even gave 777 permission to the /tmp , /update and /application/config folders after uploading the files, and even then I only get an error 500 as a result. Meanwhile, the old 5.4.2 version is still accessible normally in the same server (see above).

I even tried to install both the latest version and version 5.4.2 in other subdomains ( lima.mmnj.adv.br and salvia.mmnj.adv.br ), following the above procedures to the letter. Same result: error 500 . I tried to change the folder permissions on these new installations to 777, and it still gives error 500 . Meanwhile, the old 5.4.2 version is still accessible normally in the same server (see above).

Not knowing what else to do, I browsed through the forum, without finding adequate answers to my problem. Ditto for the bug tracker.

Having gone through everything recommended before posting on the forum, here I am, opening a thread and asking for help.

Translated with www.DeepL.com/Translator (free version)

A error 500 is difficult to troubleshoot.

I would remove everything from one of the new subdomains and start with uploading a simple php file.

E.g. index.php with nothing in or a phpinfo command.

<?php
phpinfo();
?>

Ensure that this is working before uploading the limesurvey package.
When using phpinfo you could check if the PHP version is compatible with the LimeSurvey version.
We don't know how your provider offer the php interpreter. Perhaps there are settings per subdomain and they differ.
You better consult your provider directly.

I don't know if it is of any relevance, but the files "config.php" and "security.php" are absent in all "broken" installations, and are both present in the "working" instalation. I just copied the whole "working" instalation from questionarios.mmnj.adv.br and uploaded it - entirely, without any modification - to iris.mmnj.adv.br . As I expected, it is fully accessible, but still has the cryptography issue that pushed me to reinstall it. Any hints?

Since you wasn't able to run the setupscript after uploading the files no config.php and security.php where created. These files are not part of the installation package and only created by the setup script.

I recommend to create another subdomain and try again. Perhaps use a different tool than Filezilla (e.g WinSCP if you use Windows) and try to upload the archive and extract it on the webserver. That way you reduce faults in uploaded files.


www.limesurvey.org/manual/Installation_-_LimeSurvey_CE

I solved everything with a simple and unexpected kludge:

1) I copied all the files and folders from the "functional" installation of questionarios.mmnj.adv.br to iris.mmnj.adv.br, including the "config.php" and "security.php" files;

2) After copying everything over, without touching anything, I deleted only the "config.php" and "security.php" files;

3) After deleting these two files, I accessed iris.mmnj.adv.br/admin

And then voilà, the installation script ran as smoothly as it was supposed to.

The problem, therefore, has been solved. Its cause, however, is still unknown.

Since I copied the whole "working" installation to my hard disk before doing anything, as soon as the schedule allows I will compare the files of this "working" installation with those of a 5.4.2 version to understand what happened.

Anyway, thanks a lot!

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