Hi,

Since Monday 02/06/2023 we cannot reach any more a specific site with domain infobit.biz

also outlook mail configuration is not more working

We have already tried:

change MTU

chande DNS

MAc clone

Disable firewall, acces control and parental control

This appens ONLY passing throws Archer MR600. Connecting directly to router or with another network work fine

We have this configuration:
LAN/AN port with a public IP and clients connecting through cable with fixed IP address, clients connecting through wi-fi via DHCP (correctly configured as reported in manuals)

This problem only happens with listed hosts and having done some troubleshooting with wiresharks gives lots of 

Frame 53: 66 bytes on wire (528 bits), 66 bytes captured (528 bits) on interface \Device\NPF_{393CACEB-F0C7-4568-BFCE-3B85AEEA8352}, id 0
    Interface id: 0 (\Device\NPF_{393CACEB-F0C7-4568-BFCE-3B85AEEA8352})
    Encapsulation type: Ethernet (1)
    Arrival Time: Feb  9, 2023 12:39:34.597139000 ora solare Europa occidentale
    [Time shift for this packet: 0.000000000 seconds]
    Epoch Time: 1675942774.597139000 seconds
    [Time delta from previous captured frame: 0.293696000 seconds]
    [Time delta from previous displayed frame: 0.293696000 seconds]
    [Time since reference or first frame: 11.585465000 seconds]
    Frame Number: 53
    Frame Length: 66 bytes (528 bits)
    Capture Length: 66 bytes (528 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ethertype:ip:tcp]
    [Coloring Rule Name: Bad TCP]
    [Coloring Rule String: tcp.analysis.flags && !tcp.analysis.window_update && !tcp.analysis.keep_alive && !tcp.analysis.keep_alive_ack]
Ethernet II, Src: Chongqin_18:a2:6f (74:12:b3:18:a2:6f), Dst: TP-Link_c9:5c:91 (54:af:97:c9:5c:91)
    Destination: TP-Link_c9:5c:91 (54:af:97:c9:5c:91)
        Address: TP-Link_c9:5c:91 (54:af:97:c9:5c:91)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Source: Chongqin_18:a2:6f (74:12:b3:18:a2:6f)
        Address: Chongqin_18:a2:6f (74:12:b3:18:a2:6f)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 192.168.1.110, Dst: 185.4.176.102
    0100 .... = Version: 4
    .... 0101 = Header Length: 20 bytes (5)
    Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
        0000 00.. = Differentiated Services Codepoint: Default (0)
        .... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    Total Length: 52
    Identification: 0x5b47 (23367)
    Flags: 0x40, Don't fragment
        0... .... = Reserved bit: Not set
        .1.. .... = Don't fragment: Set
        ..0. .... = More fragments: Not set
    ...0 0000 0000 0000 = Fragment Offset: 0
    Time to Live: 128
    Protocol: TCP (6)
    Header Checksum: 0x73fb [validation disabled]
    [Header checksum status: Unverified]
    Source Address: 192.168.1.110
    Destination Address: 185.4.176.102
Transmission Control Protocol, Src Port: 50671, Dst Port: 993, Seq: 0, Len: 0
    Source Port: 50671
    Destination Port: 993
    [Stream index: 2]
    [Conversation completeness: Incomplete, SYN_SENT (1)]
    [TCP Segment Len: 0]
    Sequence Number: 0    (relative sequence number)
    Sequence Number (raw): 3709052328
    [Next Sequence Number: 1    (relative sequence number)]
    Acknowledgment Number: 0
    Acknowledgment number (raw): 0
    1000 .... = Header Length: 32 bytes (8)
    Flags: 0x002 (SYN)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgment: Not set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish request (SYN): server port 993]
                [Connection establish request (SYN): server port 993]
                [Severity level: Chat]
                [Group: Sequence]
        .... .... ...0 = Fin: Not set
        [TCP Flags: ··········S·]
    Window: 64240
    [Calculated window size: 64240]
    Checksum: 0xfc10 [unverified]
    [Checksum Status: Unverified]
    Urgent Pointer: 0
    Options: (12 bytes), Maximum segment size, No-Operation (NOP), Window scale, No-Operation (NOP), No-Operation (NOP), SACK permitted
        TCP Option - Maximum segment size: 1460 bytes
            Kind: Maximum Segment Size (2)
            Length: 4
            MSS Value: 1460
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - Window scale: 8 (multiply by 256)
            Kind: Window Scale (3)
            Length: 3
            Shift count: 8
            [Multiplier: 256]
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - SACK permitted
            Kind: SACK Permitted (4)
            Length: 2
    [Timestamps]
        [Time since first frame in this TCP stream: 7.015509000 seconds]
        [Time since previous frame in this TCP stream: 4.001052000 seconds]
    [SEQ/ACK analysis]
        [TCP Analysis Flags]
            [Expert Info (Note/Sequence): A new tcp session is started with the same ports as an earlier session in this trace]
                [A new tcp session is started with the same ports as an earlier session in this trace]
                [Severity level: Note]
                [Group: Sequence]
            [Expert Info (Note/Sequence): This frame is a (suspected) retransmission]
                [This frame is a (suspected) retransmission]
                [Severity level: Note]
                [Group: Sequence]
            [The RTO for this segment was: 7.015509000 seconds]
            [RTO based on delta from frame: 21]