T26 V73 unable transfering incoming calls

[Flora_Yealink]

HI ,
I try to reproduce the issue in my side but can't, the phone works well, would you please help check if any steps are not the same as your?
1. Phone A T26 with version 6.73.0.50, register an account 104, 104 are in the ring group ,group number 123
2. another phone B 111 make a call to 123, 104 rings
3.104 answers the call, 111 and 104 are in the call
4. 104 press " Transfer" button , it will enter to "Transfer to " button , the you can enter the number you want to transfer the call to .
5. enter the number 108 + press OK button , the 108 will ring.
so it seems normal , would you please share us the details steps include the result and the expected result？
Best Regards!
Flora