[FIXED] PHPMyAdmin 500 Internal Server Error in Apache due to PHP Version

Issue

Version:

• OS lsb_release -a : Ubuntu 18.04.5 LTS
• PHP php -v : 8.0.1
• Apache apache2 -v : 2.4.29 (Ubuntu)
• MySQL mysql --version : mysql Ver 14.14 Distrib 5.7.32

---

Problem:

I'm trying to install LAMP Stack using following article. However, I was getting HTTP 500 Error while accessing phpmyadmin from browser.

And installed phpmyadmin using below command.

• sudo apt install phpmyadmin php-mbstring php-zip php-gd php-json php-curl

---

Tried :

So, I checked with Error Log tail -f /var/log/apache2/error.log and found that Phpmyadmin was running on depreciated version of PHP.

[Sat Jan 30 12:56:38.798871 2021] [php:error] [pid 17271] [client 
103.25.169.179:28514] PHP Fatal error:  Array and string offset access 
syntax with curly braces is no longer supported in 
/usr/share/phpmyadmin/libraries/Util.php on line 2087

[Sat Jan 30 12:56:38.798871 2021] [php:error] [pid 17271] [client 103.25.169.179:28514] PHP Fatal error:  Uncaught ValueError: 
mb_convert_encoding(): Argument #2 ($to_encoding) must be a valid 
encoding, "" given in /usr/share/php/php-php-
gettext/gettext.inc:181\nStack trace:\n#0 /usr/share/php/php-php-
gettext/gettext.inc(181): mb_convert_encoding()\n#1 /usr/share/php/php-
php-gettext/gettext.inc(278): _encode()\n#2 /usr/share/php/php-php-
gettext/gettext.inc(285): _gettext()\n#3 
/usr/share/phpmyadmin/libraries/sanitizing.lib.php(179): __()\n#4 
/usr/share/phpmyadmin/libraries/Message.php(607): PMA_sanitize()\n#5 
/usr/share/phpmyadmin/libraries/Message.php(672): 
PMA\\libraries\\Message::decodeBB()\n#6 
/usr/share/phpmyadmin/libraries/Error.php(220): PMA\\libraries\\Message-
>getMessage()\n#7 /usr/share/phpmyadmin/libraries/ErrorHandler.php(193): 
PMA\\libraries\\Error->getHash()\n#8 
/usr/share/phpmyadmin/libraries/ErrorHandler.php(156): 
PMA\\libraries\\ErrorHandler->addError()\n#9 [internal function]: 
PMA\\libraries\\ErrorHandler->handleError()\n#10 
/usr/share/phpmyadmin/libraries/session.inc.php(133): ini_set()\n#11 
/usr/share/phpmyadmin/libraries/common.inc.php(280): require('...')\n#12 
/usr/share/phpmyadmin/index.php(13): require_once('...')\n#13 {main}\n  
thrown in /usr/share/php/php-php-gettext/gettext.inc on line 181

• I'd solved Array and string offset access syntax error by removing { } with [ ]
• Run the following command sudo phpenmod mbstring

Solution

Important:

Please change the version number to get more security if you have phpMyAdmin exposed to the public or need features from newer phpMyAdmin versions.

This was taken from a chat. Some things might be inaccurate, but this solved the OP's problem

Install PHPMyAdmin using the following tutorial:

1.

apt purge phpmyadmin -y

cd /path/to/somefolder

wget https://files.phpmyadmin.net/phpMyAdmin/5.1.0-rc1/phpMyAdmin-5.1.0-rc1-all-languages.zip && unzip phpMyAdmin-5.1.0-rc1-all-languages.zip && 
cd phpMyAdmin-5.1.0-rc1-all-languages

apt install pwgen -y

5. Make note of the output of this command, I will refer to it as pw

pwgen -s 32 1

cp config.sample.inc.php config.inc.php

7. Edit config.inc.php with favorite editor, and paste the pw in this line:

. . .
$cfg['blowfish_secret'] = 'STRINGOFTHIRTYTWORANDOMCHARACTERS'; /* YOU MUST FILL IN THIS FOR COOKIE AUTH! */
. . .

vim /etc/apache2/conf-available/phpmyadmin-custom.conf

9. Paste the following to that previous command:

Alias /phpmyadmin /path/to/that/phpMyAdmin-5.1.0-rc1-all-languages
<Directory "/path/to/that/phpMyAdmin-5.1.0-rc1-all-languages">
Options SymLinksIfOwnerMatch
DirectoryIndex index.php
Require all granted
</Directory>

10. Save the previous one using :wq, Run the following command

a2enconf phpmyadmin-custom && systemctl restart apache2 && mysql

11. Replace your_password_here to your own password.

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'your_password_here';

systemctl restart mysql

It should work now.

Additional notes:

To only allow you to view phpMyAdmin, try:

<Directory "/path/to/that/phpMyAdmin-5.1.0-rc1-all-languages">
Options SymLinksIfOwnerMatch
DirectoryIndex index.php
Require local
# Or change it to
# Require ip 127.0.0.1
# change 127.0.0.1 to your personal computers ip address,
# not to the server ip
# if you want to access phpMyAdmin from a public server, but not allow others to access it
</Directory>

Answered By - Example person