Unable to pickup incoming calls

[Flora_Yealink]

Thanks for your information .
From your description , it seems you use the sequently ring method which means , ring group number has a call,the first handset will ring. If the ring group number has new incoming call, the second handset will ring..
It is configured in the server side, please refer to attached file.
From the BLF setting, it seems you didn't configure the extension value which should be used to configure pick up value.
In this case, please enable the direct call pickup feature and configure the pick up value for example for 3CX, the pickup value is *20*.
please refer to attached file.