ACK request is sent after 3 seconds after [RST, ACK]. HTTPWATCHER says ERROR_INTERNET_CONNECTION_RESET

Hi, sometimes I get error, I use HTTPWATCHER, it says ERROR_INTERNET_CONNECTION_RESET + 10.801 1 1.374 570 4549 GET ERROR_INTERNET_CONNECTION_RESET json http://XXX/customers/42239

Wireshark shows

3075    60.313958000    10.61.21.55 10.61.21.136    TCP 66  50  51374→8080 [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1
3077    60.314483000    10.61.21.136    10.61.21.55 TCP 66  50  8080→51374 [SYN, ACK] Seq=0 Ack=1 Win=5840 Len=0 MSS=1460 SACK_PERM=1 WS=128
3078    60.314528000    10.61.21.55 10.61.21.136    TCP 54  50  51374→8080 [ACK] Seq=1 Ack=1 Win=65536 Len=0
3082    60.315901000    10.61.21.55 10.61.21.136    HTTP    501 50  GET /XXX/customers/42239 HTTP/1.1 
3084    60.316415000    10.61.21.136    10.61.21.55 TCP 60  50  8080→51374 [ACK] Seq=1 Ack=448 Win=6912 Len=0
3115    63.459427000    10.61.21.55 10.61.21.136    TCP 54  50  51374→8080 [RST, ACK] Seq=448 Ack=1 Win=0 Len=0

All request from IE11 Help understand reasons