compiler error

[pvdw0310]

Hi, I try to compile the scan sample and get a compiler error :

.....

"C:\\Program Files (x86)\\Arduino\\tools-builder\\ctags\\5.8-arduino11/ctags" -u --language-force=c++ -f - --c++-kinds=svpf --fields=KSTtzns --line-directives "C:\\Users\\peter\\AppData\\Local\\Temp\\arduino_build_888210\\preproc\\ctags_target_for_gcc_minus_e.cpp"
Bezig met het compileren van de schets...
"C:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\tools\\xtensa-esp32-elf-gcc\\1.22.0-80-g6c4433a-5.2.0/bin/xtensa-esp32-elf-g++" -DESP_PLATFORM "-DMBEDTLS_CONFIG_FILE=\"mbedtls/esp_config.h\"" -DHAVE_CONFIG_H -DGCC_NOT_5_2_0=0 -DWITH_POSIX "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/config" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/app_trace" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/app_update" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/asio" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/bootloader_support" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/bt" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/coap" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/console" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/driver" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp-tls" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp32" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp_adc_cal" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp_event" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp_http_client" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp_http_server" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp_https_ota" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp_ringbuf" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/ethernet" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/expat" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/fatfs" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/freemodbus" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/freertos" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/heap" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/idf_test" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/jsmn" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/json" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/libsodium" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/log" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/lwip" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/mbedtls" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/mdns" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/micro-ecc" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/mqtt" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/newlib" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/nghttp" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/nvs_flash" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/openssl" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/protobuf-c" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/protocomm" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/pthread" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/sdmmc" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/smartconfig_ack" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/soc" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/spi_flash" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/spiffs" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/tcp_transport" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/tcpip_adapter" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/ulp" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/vfs" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/wear_levelling" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/wifi_provisioning" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/wpa_supplicant" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/xtensa-debug-module" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp-face" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp32-camera" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/esp-face" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4/tools/sdk/include/fb_gfx" -std=gnu++11 -Os -g3 -Wpointer-arith -fexceptions -fstack-protector -ffunction-sections -fdata-sections -fstrict-volatile-bitfields -mlongcalls -nostdlib -w -Wno-error=maybe-uninitialized -Wno-error=unused-function -Wno-error=unused-but-set-variable -Wno-error=unused-variable -Wno-error=deprecated-declarations -Wno-unused-parameter -Wno-unused-but-set-parameter -Wno-missing-field-initializers -Wno-sign-compare -fno-rtti -MMD -c -DF_CPU=240000000L -DARDUINO=10813 -DARDUINO_D1_MINI32 -DARDUINO_ARCH_ESP32 "-DARDUINO_BOARD=\"D1_MINI32\"" "-DARDUINO_VARIANT=\"d1_mini32\"" -DESP32 -DCORE_DEBUG_LEVEL=0 "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4\\cores\\esp32" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4\\variants\\d1_mini32" "-IC:\\Users\\peter\\Documents\\Arduino\\libraries\\WiFiNINA\\src" "-IC:\\Users\\peter\\Documents\\Arduino\\libraries\\Sonos-ESP32\\src" "-IC:\\Users\\peter\\Documents\\Arduino\\libraries\\microxpath\\src" "-IC:\\Users\\peter\\Documents\\Arduino\\libraries\\EasyWifi-for-MKR1010-main\\src" "-IC:\\Users\\peter\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.4\\libraries\\SPI\\src" "C:\\Users\\peter\\AppData\\Local\\Temp\\arduino_build_888210\\sketch\\SonosScan.ino.cpp" -o "C:\\Users\\peter\\AppData\\Local\\Temp\\arduino_build_888210\\sketch\\SonosScan.ino.cpp.o"
SonosScan:41:12: error: cannot declare variable 'G_Myserver' to be of abstract type 'WiFiServer'
 WiFiServer G_Myserver(SERVER_PORT);
            ^
In file included from C:\Users\peter\Documents\Arduino\libraries\WiFiNINA\src/WiFi.h:36:0,
                 from C:\Users\peter\Documents\Arduino\libraries\WiFiNINA\src/WiFiNINA.h:23,
                 from C:\Users\peter\Documents\Arduino\libraries\Sonos-ESP32\examples\SonosScan\SonosScan.ino:26:
C:\Users\peter\Documents\Arduino\libraries\WiFiNINA\src/WiFiServer.h:32:7: note:   because the following virtual functions are pure within 'WiFiServer':
 class WiFiServer : public Server {
       ^
In file included from C:\Users\peter\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.4\cores\esp32/Arduino.h:152:0,
                 from C:\Users\peter\AppData\Local\Temp\arduino_build_888210\sketch\SonosScan.ino.cpp:1:
C:\Users\peter\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.4\cores\esp32/Server.h:28:18: note: 	virtual void Server::begin(uint16_t)
     virtual void begin(uint16_t port=0) =0;
                  ^
Bibliotheek WiFiNINA op versie 1.8.7 in map: C:\Users\peter\Documents\Arduino\libraries\WiFiNINA  wordt gebruikt
Bibliotheek Sonos-ESP32 op versie 1.2 in map: C:\Users\peter\Documents\Arduino\libraries\Sonos-ESP32  wordt gebruikt
Bibliotheek microxpath op versie 1.1 in map: C:\Users\peter\Documents\Arduino\libraries\microxpath  wordt gebruikt
Bibliotheek EasyWifi-for-MKR1010-main op versie 1.3.0 in map: C:\Users\peter\Documents\Arduino\libraries\EasyWifi-for-MKR1010-main  wordt gebruikt
Bibliotheek SPI op versie 1.0 in map: C:\Users\peter\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.4\libraries\SPI  wordt gebruikt
exit status 1
cannot declare variable 'G_Myserver' to be of abstract type 'WiFiServer'

I'am not good to solving compiler problems, have you an idea what went wrong?
Thanks to point me in the right direction.
Peter