Trying to connect to a Skywatcher Viruoso mount the connection fails with "child process died" message.
I've run the indiserver under gdb, but it did not caught an exception. I attach the output of the gdb session and the log of the driver

The operating system is Ubuntu 18.04: 4.18.0-15-generic #16~18.04.1-Ubuntu
INDI Library: 1.8.4
Code 1.8.4-tgz. Protocol 1.7.

This time I got a bit more detailed log from Ekos:

org.kde.kstars.indi: Skywatcher Alt-Az : "[DEBUG] Connecting to /dev/ttyUSB0 @ 9600 "
org.kde.kstars.indi: Skywatcher Alt-Az : "[DEBUG] Port FD 4 "
org.kde.kstars.indi: Skywatcher Alt-Az : "[DEBUG] Connection successful, attempting handshake... "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] SkywatcherAPIMount::Handshake "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] InitMount "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] CheckIfDCMotor "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] GetMicrostepsPerRevolution "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] Axis 0: 2402.916667 microsteps/degree, 0.667477 microsteps/arcsec "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] GetMicrostepsPerRevolution "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] Axis 1: 2402.916667 microsteps/degree, 0.667477 microsteps/arcsec "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] GetStepperClockFrequency "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] GetStepperClockFrequency "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] GetHighSpeedRatio "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] GetHighSpeedRatio "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] Encoders before init Axis1 8388608 Axis2 8388608 "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] InitializeMC "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] Encoders after init Axis1 8388608 Axis2 8388608 "
Dispatch command error(-1):
<setSwitchVector device="Skywatcher Alt-Az" name="TELESCOPE_PARK" state="Ok" timeout="60" timestamp="2020-02-14T21:43:58">
<oneSwitch name="PARK">
On
</oneSwitch>
<oneSwitch name="UNPARK">
Off
</oneSwitch>
</setSwitchVector>
org.kde.kstars.indi: Skywatcher Alt-Az : "[INFO] Mount is parked. "
org.kde.kstars.indi: Skywatcher Alt-Az : "[SCOPE] SkywatcherAPIMount::Handshake - Result: 1 "
org.kde.kstars.indi: Skywatcher Alt-Az : "[INFO] Skywatcher Alt-Az is online. "
org.kde.kstars.indi: Skywatcher Alt-Az : "[DEBUG] Configuration successfully saved for DEVICE_PORT. "
org.kde.kstars.indi: Skywatcher Alt-Az : "[DEBUG] Configuration successfully saved for DEVICE_BAUD_RATE. "
org.kde.kstars.indi: Skywatcher Alt-Az : "[DEBUG] Configuration successfully saved for CONNECTION_MODE. "
org.kde.kstars.ekos: Skywatcher Alt-Az Version: "1.0" Interface: 1 is connected.
org.kde.kstars.ekos: 1 devices connected out of 2
Dispatch command error(-1): No device available and none was created
<defNumberVector device="" name="" label="" group="" state="Idle" perm="ro" timeout="0" timestamp="2020-02-14T21:43:58"/>
Dispatch command error(-1): No device available and none was created
<defNumberVector device="" name="" label="" group="" state="Idle" perm="ro" timeout="0" timestamp="2020-02-14T21:43:58"/>
Dispatch command error(-1): Cannot delete property DEBUG_LEVEL as it is not defined yet. Check driver.
<delProperty device="Skywatcher Alt-Az" name="DEBUG_LEVEL" timestamp="2020-02-14T21:43:58"/>
Dispatch command error(-1): Cannot delete property LOGGING_LEVEL as it is not defined yet. Check driver.
<delProperty device="Skywatcher Alt-Az" name="LOGGING_LEVEL" timestamp="2020-02-14T21:43:58"/>
Dispatch command error(-1): Cannot delete property LOG_OUTPUT as it is not defined yet. Check driver.
<delProperty device="Skywatcher Alt-Az" name="LOG_OUTPUT" timestamp="2020-02-14T21:43:58"/>
Dispatch command error(-1): Cannot delete property SYSTEM_PORTS as it is not defined yet. Check driver.
<delProperty device="Skywatcher Alt-Az" name="SYSTEM_PORTS" timestamp="2020-02-14T21:43:58"/>
org.kde.kstars.indi: < Skywatcher Alt-Az >: < ON_COORD_SET >
org.kde.kstars.ekos: "Skywatcher Alt-Az is online."
qrc:/qml/mount/mountbox.qml:274: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:280: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:288: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:324: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:352: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:372: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:391: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:410: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:429: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:448: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:477: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:535: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:553: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:570: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:580: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:589: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:596: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:606: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:613: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:632: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:643: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:655: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:667: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:686: ReferenceError: xi18n is not defined
qrc:/qml/mount/mountbox.qml:695: ReferenceError: xi18n is not defined
org.kde.kstars.indi: < Skywatcher Alt-Az >: < EQUATORIAL_EOD_COORD >
org.kde.kstars.ekos: "Skywatcher Alt-Az is online."
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TELESCOPE_ABORT_MOTION >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TELESCOPE_MOTION_NS >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TELESCOPE_MOTION_WE >
org.kde.kstars.indi: INDI Server: "2020-02-14T21:43:58: Driver indi_skywatcherAltAzMount: stderr EOF"
org.kde.kstars.indi: INDI Server: "<delProperty device=\"Skywatcher Alt-Az\"/>"
org.kde.kstars.indi: INDI Server: "Child process 2647 died"
org.kde.kstars.indi: INDI Server: "2020-02-14T21:43:58: Driver indi_skywatcherAltAzMount: Terminated after #0 restarts."
org.kde.kstars.indi: INDI Server: ""
org.kde.kstars.indi: INDI driver "indi_skywatcherAltAzMount" crashed!
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TELESCOPE_SLEW_RATE >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TARGET_EOD_COORD >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TIME_UTC >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < GEOGRAPHIC_COORD >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TELESCOPE_PARK >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < APPLY_SCOPE_CONFIG >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < USEJOYSTICK >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < BASIC_MOUNT_INFO >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < AXIS_ONE_INFO >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < AXIS_ONE_STATE >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < AXIS_TWO_INFO >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < AXIS_TWO_STATE >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < AXIS1_ENCODER_VALUES >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < AXIS2_ENCODER_VALUES >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TELESCOPE_MOTION_SLEWMODE >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < TELESCOPE_MOTION_SOFTPECMODE >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < SOFTPEC >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < GUIDE_RATES >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < PARK_DIRECTION >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < PARK_POSITION >
org.kde.kstars.indi: < Skywatcher Alt-Az >: < UNPARK_POSITION >
Dispatch command error(-1): No device available and none was created
<defNumberVector device="" name="" label="" group="" state="Idle" perm="ro" timeout="0" timestamp="2020-02-14T21:43:58"/>
Dispatch command error(-1): No device available and none was created
<defNumberVector device="" name="" label="" group="" state="Idle" perm="ro" timeout="0" timestamp="2020-02-14T21:43:58"/>
org.kde.kstars.indi: Skywatcher Alt-Az : "[INFO] Loading device configuration... "
org.kde.kstars.indi: Skywatcher Alt-Az : "[INFO] Debug is disabled. "
org.kde.kstars.ekos: "Re-enabling debug logging for Skywatcher Alt-Az..."
org.kde.kstars.indi: < Skywatcher Alt-Az >: < SYSTEM_PORTS >
org.kde.kstars.indi: Removing device Skywatcher Alt-Az
org.kde.kstars.indi: INDIListener: Removing device Skywatcher Alt-Az with unique label "Skywatcher Alt-Az"
org.kde.kstars.ekos: "Skywatcher Alt-Az is offline."
org.kde.kstars.indi: INDI: Stopping local drivers...
org.kde.kstars.indi: Removing managed driver "Skywatcher Alt-Az"
org.kde.kstars.indi: INDIListener: Removing device Skywatcher Alt-Az with unique label "Skywatcher Alt-Az"
org.kde.kstars.indi: Removing managed driver "CCD Simulator"
org.kde.kstars.indi: INDIListener: Removing device CCD Simulator with unique label ""
org.kde.kstars.indi: INDIListener: Removing client manager for server localhost @ 7624