Is everything else working fine on the wifi? I assume the camera will be 2.4 GHz only is it a "long way" from the Hub3 ? You will probably get a more reliable connection if you do these tweaks (assuming you haven't yet).
Go into the Hub3 settings (go to http://192.168.0.1 or http://192.168.100.1 in your browser) and in "smart wifi" disable the "channel optimisation". Then, in advanced>wireless>security, rename the 2.4 & 5 GHz network ssid's. Just change 'em to whatever you like and something that will differentiate them - e.g - xxxxx2 & xxxxx5) use the same password if you like, Then, save settings and restart Hub. Your 2 wifi networks will now be clearly separated and you can then select the network you want to connect to, individually on each device. 5 GHz is usually better and subject to less interference than the 2.4 one - although this one has the better "range". Select that 2.4 network on the camera and see if it connects - report back,
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