Make sure that the audio source is playing and has sufficient gain.

Make sure you have activated a channel in the app (indicated by blue light).

Make sure that the mobile device's volume is turned up.

Make sure that the mobile device's headphones/loudspeakers are working properly.

Check the audio source for any interference.

Make sure the input sensitivity and gain settings of the audio source as well as the gain settings of the ConnectStation are adjusted correctly.

Make sure you have a direct line of sight to the WiFi AP.

Disable location based service (Android devices).

Try to disable Mobile data or enter Airplane mode with WiFi on the mobile device. In a WiFi without internet, the mobile device will try to stay connected using mobile data and can cause interference with the audio streaming.

Use a WiFi analyser software to make sure to use a channel where no other WiFi or disturber is active as well as the gain settings of the ConnectStation are adjusted correctly.

Make sure the audio source is not delayed. Please note that every additional audio device (mixing console, amplifier, etc.) between the source and the ConnectStation audio input may increase the latency.

Make sure you have a direct line of sight to the WiFi AP.

Mobile devices, especially Android phones, can add a higher latency (see "List of tested mobile devices").

Wireless headphones may have a higher latency than wired headphones, which do not add any latency.

Check the audio source.

Check the amplitude of the audio signal in the Input Levels tab on the Audio Inputs page of the Admin Interface. See "Audio Inputs" in section "General configuration".

Make sure the amplitude is high enough. If it is always lower the -20 dB, increase the sensitivity of the analog audio input from +4 dBu to -10 dBu.

Enable the AGC. If the audio level remains low, increase the parameter ratio from 2:1 to 3:1 or higher. Alternatively, reduce the threshold from -40 dB to -60 dB or -80 dB to provide extra gain on the low-volume portions of the input.

In case you are streaming from a microphone or other noisy source:
Adjust the noise threshold and noise gain in the AGC tab on the Audio Inputs page of the Admin Interface. See "Audio Inputs" in section "General configuration".
Increasing the noise threshold, e.g. from -80 dB to -60 dB, will cause the noise gate to trigger faster. This results in less noise streaming, however, risking to reduce the non-noise portions of the audio.
Decreasing the noise gain, e.g. from -10 dB to -20 dB, will increase the attenuation of the noise.

Check the amplitude of the audio signal in the Input Levels tab on the Audio Inputs page of the Admin Interface. See "Audio Inputs" in section "General configuration". If the audio level is too high, reduce the analog input sensitivity to +4 dBu.