what is your configuration of tenor?
countrycode and area code?
as for me countrycode is 86 and areacode is 21
so i config tenor as follow:
config,iptg,
outdeletedigit 4 ,outprefix 8621,
incomdeletedigit 4 incomingprefix 8621 and i didnot remenber any setting on welltech’s phone.
maybe you can try.
good luck