User entered nothing

I have Asterisk Server 1.8 installed which has one extension 6000 with the following configurations in the extensions.conf:

exten => 6000,n,Hangup()

but when I dial through 3CX soft phone, over the Asterisk Console, I get the following logs:

– Executing [6000@users:1] Answer(“SIP/6001-000000c5”, “500”) in new stack
– Executing [6000@users:2] Read(“SIP/6001-000000c5”, “digito,20,skip,2,5”) in new stack
– Accepting a maximum of 20 digits.
– User entered nothing, 1 chance left
– User entered nothing.
– Executing [6000@users:3] SayDigits(“SIP/6001-000000c5”, “”) in new stack
– Executing [6000@users:4] Hangup(“SIP/6001-000000c5”, “”) in new stack

Can anybody please let me know why during the call, it’s not accepting the digits entered in the 3CX soft phone?

Waiting for your precious thoughts.

Thanks a lot.