The participant's internet connection speed reported by the browser is below the minimum recommended threshold. A slow connection speed can cause dropouts or delays in the live voip audio as well as slow or failed uploads of the recorded audio.
If the guest is using a wifi or tethering on their mobile phone connection, have them switch to a wired internet connection if possible.
If you can hear each other well enough through the voip connection, then it is probably fine to proceed with recording. It will be a good idea to keep an eye on the cloud backup progress during the recording to ensure that is isn't getting behind.