why i encounter this error every single day to get orderbook with websocket

[JohnsonHsiao]

[2023-07-15 06:09:55,919 ERROR] error from callback <bound method BitgetWsClient.__on_message of <src.sdks.bitget.ws.bitget_ws_client.BitgetWsClient object at 0x000001E00874B640>>: can only concatenate str (not "Bitget") to str
[2023-07-15 06:09:56,496 INFO ] Websocket connected
[2023-07-15 06:09:58,527 INFO ] Websocket connected
[2023-07-15 06:10:20,897 ERROR] error from callback <bound method BitgetWsClient.__on_message of <src.sdks.bitget.ws.bitget_ws_client.BitgetWsClient object at 0x000001E00874B640>>: can only concatenate str (not "Bitget") to str
[2023-07-15 06:10:21,368 INFO ] Websocket connected
[2023-07-15 06:10:23,597 INFO ] Websocket connected
[2023-07-15 06:10:45,939 ERROR] error from callback <bound method BitgetWsClient.__on_message of <src.sdks.bitget.ws.bitget_ws_client.BitgetWsClient object at 0x000001E00874B640>>: can only concatenate str (not "Bitget") to str
[2023-07-15 06:10:46,447 INFO ] Websocket connected
[2023-07-15 06:10:48,889 INFO ] Websocket connected