Describe the bug

I know this might not to do with Graph SDK but a server side issue, but I don't have a easy path the report this. Since we are using Graph SDK to query external connection Api, people might have seen this issue as well.

This is Graph SDK returns via : graphClient
.External
.Connections[SearchConnectorName]
.Items[itemId.ToString()]
.GetAsync(default, cancellationToken);
ODataError:

    img {
        border: 0 none;
    }

    #content {
        margin-left: auto;
        margin-right: auto
    }

    #message h1 {
        font-size: 24px;
        font-weight: normal;
        color: #000000;
        margin: 34px 0px 0px 0px
    }

    #message h2 {
        font-size: 20px;
        font-weight: normal;
        color: #000000;
        margin: 34px 0px 0px 0px
    }

    #message p {
        font-size: 16px;
        color: #000000;
        margin: 8px 0px 0px 0px
    }

    #message hr {
        margin: 15px 0px
    }

    #errorref {
        font-size: 11px;
        color: #737373;
        margin-top: 41px
    }
</style>
<title>Service unavailable</title>

And this is what postman returns with the same Api:
https://graph.microsoft.com/v1.0/external/connections/[SearchConnectorName]/items/[ItemId]:
{
"error": {
"code": "UnknownError",
"message": "\n\n\n\n \n <style type='text/css'>\n body {\n font-family: Arial;\n margin-left: 40px;\n }\n\n img {\n border: 0 none;\n }\n\n #content {\n margin-left: auto;\n margin-right: auto\n }\n\n #message h1 {\n font-size: 24px;\n font-weight: normal;\n color: #000000;\n margin: 34px 0px 0px 0px\n }\n\n #message h2 {\n font-size: 20px;\n font-weight: normal;\n color: #000000;\n margin: 34px 0px 0px 0px\n }\n\n #message p {\n font-size: 16px;\n color: #000000;\n margin: 8px 0px 0px 0px\n }\n\n #message hr {\n margin: 15px 0px\n }\n\n #errorref {\n font-size: 11px;\n color: #737373;\n margin-top: 41px\n }\n </style>\n <title>Service unavailable</title>\n\n\n\n

Expected behavior

The External Item Api should be reliably return response rather than random throw front door error

How to reproduce

1. Query external Item api via Graph SDK
2. The Api is very slow (takes about 10 seconds to return if succeeded)
3. The Api failed randomly with the exception above

SDK Version

No response

Latest version known to work for scenario above?

6.5

Known Workarounds

The Api is throwing frontdoor error randomly

Debug output

</details>


### Configuration

_No response_

### Other information

_No response_