Cannot get full error message of `LogfmtParserErr`

Grafana Loki
1

When querying Loki, either with logcli or HTTP API i get response:

2023-09-29T09:51:24Z {__error__="LogfmtParserErr"}

or

{
    "data": {
        "result": [
            {
                "stream": {
                    "Log": "", 
                    "_09_51_30": "", 
                    "_0m": "", 
                    "_0m_8_": "", 
                    "_34m_INFO_": "", 
                    "__error__": "LogfmtParserErr", 
                    "container": "test", 
                    "dump_": "", 
                    "dump_id": "d17b2c5b-5542-4509-82e5-2840b842ccc1", 
                    "filename": "/var/lib/docker/containers/xxx/xxx-json.log", 
                    "job": "containerlogs", 
                    "lib__actors__log_actor_": "", 
                    "stream": "stdout", 
                    "tag": "xxx/xxx/test:1.0.0|test_1|sha256:xxx|xxx"
                }, 
                "values": [
                    [
                        "1695981090372399013", 
                        ""
                    ], 
                    [
                        "1695981090370931852", 
                        ""
                    ]
                ]
            },
        ]
    }
}

But I cant get this error message. Tried to add -log.level=debug CLI parameter to loki startup command and &log_level=debug to API request, but no effect. Docker logs for loki container don’t show anything useful neither.

Can’t find any info how to increase verbosity of this LogfmtParserErr to get full message.

Where I can find it?