In Mongo logs there are intermittent entries below. During same time it is observed that the C# APIs accessing data from MongoDB timeout with 504 error. Please suggest the root cause of this problem and probable solution. Sharing sample log lines below:

I WRITE    [LogicalSessionCacheRefresh] update config.system.sessions command: { q: { _id:

{ id: UUID("0c9936f3-8cbd-4518-ab7e-93a4c68138c7"), uid: BinData(0, 3B408CB48548B5037822C10EB0976B3CBF2CEE3BF9C708796BF03941FBECD80F) }

}, u: { $currentDate:

{ lastUse: true }

, $setOnInsert: { user:

{ name: "admin@admin" }

} }, multi: false, upsert: true } planSummary: IDHACK keysExamined:0 docsExamined:0 nMatched:0 nModified:0 upsert:1 keysInserted:2 numYields:1 locks:{ Global: { acquireCount:

{ r: 2, w: 2 }

}, Database: { acquireCount:

{ w: 2 }

}, Collection: { acquireCount:

{ w: 2 }

} } 10497ms

I COMMAND  [LogicalSessionCacheRefresh] command config.$cmd command: update { update: "system.sessions", ordered: false, allowImplicitCollectionCreation: false, writeConcern:

{ w: "majority", wtimeout: 15000 }

, $db: "config" } numYields:0 reslen:97965 locks:{ Global: { acquireCount:

{ r: 1002, w: 1002 }

}, Database: { acquireCount:

{ w: 1002 }

}, Collection: { acquireCount:

{ w: 1002 }

} } protocol:op_msg 10576ms