CentOS 8 x86_64

Hey Andrea,

Could you please send us the Debug for the Frontend so we could analyse it a little further?
You can enable the Debug mode for frontend in:

Administration > Users > (select your user) > Groups > (add user to group "Enabled debug mode"). 

After that, a button will apear in the bottom right part of your screen. 
Open a window as in the screenshot, press the Debug button, and send it's content to us.  

Best regards,
Victor.

Hi Victor.

I added the item_create.txt file with the debug output from the "Create item" screen. I also added the corresponding screenshot as item.png.

Best regards

Addendum.

Just discovered that also the problems page seems to be broken. Attached the error that appears while trying to filter the list by a specific host.

Andrea,

I checked the logs you sent me, and it doesn't seem to be anything out of place.
Could you describe how you performed the migration, what DBMS (Database Management System) you're using and it's version?

Best regards,
Victor

Hi Victor.

The migration path was:

1. Installed a new zabbix on a different VM, same major LTS (5.0).
2. Stopped the old zabbix server, and front-end
3. Dumped the zabbix database (including data) and restore the database as-is on the new node, using mysqldump.
4. At restore successful, I started the new zabbix server, checked that no database errors was present in the logs.
5. Started the new front-end.

The zabbix database is running under MariaDB Ver 15.1 Distrib 10.3.28-MariaDB, for Linux (x86_64) using readline 5.1.

To note: I can create items and other elements using the zabbix API. However, in one instance, adding an host with a
proxy made me create it, but after some time, the proxy setting for the host was removed.

As I previously said, the data appears to be there, as the monitoring itself is working fine. Maybe some problems with
the PHP configuration or the php version itself?

Hey Andrea,

Could you please send what packages you have installed for both Zabbix and PHP?

Please run the command below:

rpm -qa | grep zabbix; rpm -qa | grep php

Please also check the character set and collate version on Zabbix DB, and check the web-server logs for any errors.

Hi Victor.

Installed zabbix and php packages are as follows:

php-bcmath-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-cli-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-common-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-fpm-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-gd-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-json-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-ldap-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-mbstring-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-mysqlnd-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-pdo-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-pear-1.10.5-9.module_el8.3.0+2010+7c76a223.noarch
php-process-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
php-xml-7.2.24-1.module_el8.3.0+2010+7c76a223.x86_64
zabbix-agent-5.0.19-1.el8.x86_64
zabbix-apache-conf-5.0.19-1.el8.noarch
zabbix-java-gateway-5.0.19-1.el8.x86_64
zabbix-release-5.0-1.el8.noarch
zabbix-server-mysql-5.0.19-1.el8.x86_64
zabbix-web-5.0.19-1.el8.noarch
zabbix-web-deps-5.0.19-1.el8.x86_64
zabbix-web-mysql-5.0.19-1.el8.noarch

The database collation and character set are:

MariaDB [zabbix]> use zabbix;
Database changed
MariaDB [zabbix]> SELECT @@character_set_database, @@collation_database;
+--------------------------+----------------------+
| @@character_set_database | @@collation_database |
+--------------------------+----------------------+
| utf8                     | utf8_bin             |
+--------------------------+----------------------+
1 row in set (0.000 sec)

About the web server logs, nothing to see there, there are no errors both in the apache error log
and in the php-fpm error log.

Hey Andrea.

Installed packages and database collation and charset seems to be alright.

Could you please check your browser console for any error messages? If you see any error message, please send the content of it in .txt file, and a screenshot too.

Also, just for check purposes, could you try to use Zabbix Web on a different machine/browser, and, if the problem persist, could you try installing the frontend in a different server?

Regards,
Victor.

Hi Victor.

The same problems happens with other browsers, be those mobile or desktop. As you suggested, I ran
the zabbix front-end in the chrome console and, for example, while opening the item creation page, I
catched the errors attached in zabbix.host.it-1641804577727.log zabbix.host.it.*.log file attached

Next step, I'll try to install a new front-end on a different and clean virtual machine, to see if that helps.

Victor

I spun-up a test VM, installing a front-end on it and pointing it to the existing database.
'nuff said, the front-end in this case works properly. This means that, at lease, there
aren't problems with the database.

Some php-fpm configuration? there is another application running on php-fpm in the
same machine, Observium, used to monitor networking stuffs.

Ok, I found the problem.

The zabbix front-end can be accessed from internet through a reverse-proxy, that we us for various
stuffs.

Accessing the front-end directly from it's private address, doesn't present the problem. It's clear the
issue is with something related to the reverse-proxy configuration.

Sorry to have wasted your time, I didn't thought about that possibility immediately.

Regards

Final update, Victor.

Cloudflare is to blame. Their proxy broke part of the zabbix front-end. We disabled it and everything went
back to normal.

Regards