Are you able to see your Wifi network name when you scan for available networks from the printer? The printer may not support well Wifi networks where both 2.4 GHz and 5 GHz bands are grouped under the same name. If that is the cas, you can separate each WiFi band into separate WiFi network names. Then, try to connect your printer to the network name using the 2.4 GHz band.
This can be done using the Helix Fi mobile app. Once you have logged in, you can click on "View network details" in the overview tab. In the next area (My Network), you can edit the Wifi configuration using the pencil symbol in the top right corner. Please make sure to check "Use different network names for Wifi 2.4 and 5 GHz" and that both network have different names before you apply the changes. No need to change the password, it will remain the same on both networks.