====== Raspberry Pi Troubleshooting and ErgoTech Support Checks ======

This page covers common problems with a Raspberry Pi which runs MIX or TransSECS.

===== SSH says “Connection refused” =====

Example:

<code text>
ssh: connect to host ... Connection refused
</code>

SSH may not have been enabled when Raspberry Pi OS was installed.

Enable SSH through Raspberry Pi Imager when writing the card, or from a local keyboard and monitor with:

<code text>
sudo raspi-config
</code>

Choose **Interface Options -> SSH -> Yes**.

===== mix.local cannot be found =====

Try the Pi’s IP address instead:

<code text>
ssh mix@192.168.1.50
</code>

If several Pis use the same hostname on the same network, give each one a unique hostname.

===== sudo says it cannot resolve the host =====

Example:

<code text>
sudo: unable to resolve host mix: Temporary failure in name resolution
</code>

Check:

<code text>
hostname
cat /etc/hosts
</code>

The local hostname configuration in ''%%/etc/hosts%%'' must agree with the Pi’s hostname.

===== SSH or Linux commands have become very slow =====

First check disk usage:

<code text>
df -h /
</code>

Then check the system logs:

<code text>
ls -lh /var/log
ls -lh /var/log/syslog*
ls -lh /var/log/daemon.log*
</code>

A nearly full SD card can make SSH and ''%%sudo%%'' extremely slow.

If ''%%syslog%%'' or ''%%daemon.log%%'' is very large, verify the 20 MB logrotate settings in the base-setup article and verify which MIX or TransSECS console output is being written to its dedicated console log.

===== TransSECS shows a prelicense message but no number =====

If the startup message ends with ''%%prelicense code:%%'' but does not show a number, contact ErgoTech. The deployment may need to be rebuilt for the Raspberry Pi.

===== License which previously worked is rejected =====

An ErgoTech license is associated with the individual system. Changing the hostname, IP address, or network configuration does not change the license.

If a license which previously worked is rejected, contact ErgoTech and include the current pre-license information.

Each Raspberry Pi created from a master SD-card image requires its own ErgoTech license.

===== Wrong Java version =====

Check:

<code text>
java -version
</code>

If it shows Java 17 or 21 instead of Java 8:

<code text>
sudo update-alternatives --config java
</code>

Select the Java 8 installation under ''%%/opt/java%%''.

===== MIX web page does not open =====

Check whether MIX is running:

<code text>
systemctl status mix
</code>

Press **q** to leave the status screen.

If MIX is running, check the configured port:

<code text>
grep mix.port /home/mix/mixruntime/mix.properties
</code>

Also inspect the console log:

<code text>
tail -n 50 /home/mix/mixruntime/logs/runmix-console.log
</code>

===== TransSECS serial equipment does not connect =====

Check which serial devices Linux can see:

<code text>
ls /dev/ttyUSB* /dev/ttyAMA* 2>/dev/null
</code>

For SECS-I or other serial devices, also verify which ''%%run.sh%%'' includes ''%%/usr/lib/jni%%'' in ''%%LD_LIBRARY_PATH%%''.

===== Chromium says the profile appears to be in use =====

This normally follows an unclean shutdown or power loss on a MIX kiosk system.

Verify which the kiosk-specific ''%%rc.local%%'' cleanup from the kiosk article is installed, then reboot.

Do not delete Chromium lock files while Chromium is actively running.

===== The clock is wrong after a power interruption =====

For a Pi 3 or Pi 4, check:

<code text>
timedatectl
</code>

These Pis do not have a battery-backed real-time clock. ''%%fake-hwclock%%'' provides an approximate time until a network time source or another clock-setting method corrects it.

On MIX, open the setup page and use **Get Pre-License Key**, which also updates the Pi’s system time.

For a Pi 5, verify the RTC battery is installed and ''%%timedatectl%%'' shows an RTC time.

===== A service is failed or keeps restarting =====

For MIX:

<code text>
systemctl status mix
tail -n 50 /home/mix/mixruntime/logs/runmix-console.log
</code>

For TransSECS:

<code text>
systemctl status transsecs
tail -n 50 /home/mix/secs/logs/transsecs-console.log
</code>

The last lines of the console log usually contain the most useful error information.

===== Information to send ErgoTech =====

When contacting ErgoTech support, include the output of:

<code text>
uname -m
head -2 /etc/os-release
java -version
df -h /
</code>

For MIX:

<code text>
systemctl status mix
tail -n 50 /home/mix/mixruntime/logs/runmix-console.log
</code>

For TransSECS Deployments:

<code text>
systemctl status transsecs
tail -n 50 /home/mix/secs/logs/transsecs-console.log
</code>

If the problem appears related to disk space or system logging, also include:

<code text>
ls -lh /var/log/syslog*
ls -lh /var/log/daemon.log*
sudo cat /var/lib/logrotate/status
</code>