I’m required to set up WiFi devices that talk to a server, but I’m not allowed to make changes to the network. I would like to suggest to the owner of the network that it has problems, which are preventing the WiFi devices from communicating with the server. I suspect there is a high level of WiFi interference - a quick scan shows that every AP in their building is on 2.4Ghz channel 1.
Is the capture shown in the image below consistent with WiFi interference? This is a single client, which would normally make that HTTP GET request 1 - 3 times a second. On this network it is sometimes the case that the response takes up to a minute, with dozens of Dup ACK and Retransmission packets in between. Wired clients have much better connectivity and do not exhibit this extremely high rate of Dup ACK and Retransmission.