Why is leak happening

[Stefan111]

Thanks for input, newly installed concealed mixer shower valve, the hot water input keeps dripping but as can see it forms from the valve, rather than the connection point, tried PTFE, jointing compound on joint, and switched out the compression for a new push it alternative but it keeps forming.
Hiss is heard too,
Thinking could be a defect in the mixer valve rather than connection,
Thanks in advance

 

[ShaunCorbs]

Not enough ptfe tape should be around 20-25 wraps round