Facing issue of disconnect after 57 minutes in OPCUA server built on Dot net , using OPCUACore.dll version 1.5.374.158|OPC UA Standard|Forum|OPC Foundation

I have a built an  dot net  OPCUA server service using OPCUA Core dll version 1.5.374.158. The channel renewal time in the client is set to 60 minutes there is breif disconnect happening every after 57 minutes where the quality of the tags  goes bad for  3-5 seconds . I have tried all the session timeouts , publishing intervals timeouts by giving max values or anything , i have also checked if there is thread ppol starvation ut it still times out after 57 minutes. If i cahnge the reneal time to 15 minutes the disconnect and reconnect happens every after 14 minutes that is 5 % of the channel renewal time. i Have been working days end to get this resolved but cant . Please help to get this issue fixed.