Oneplus 9 5G. Unable to leave voice mail message in other TMobile subscribers voice mailboxes

Oneplus 9 5G. Unable to leave voice mail message in other T-Mobile subscribers’ voice mailboxes.
I can hold bilateral voice calls with any subscriber of any carrier.  I can leave voice messages in any other carrier's subscribers, such as ATT and Verizon, but I cannot leave message in T-Mobile subscribers as it appears that something is disabling the audio during the process of leaving a message and the T-Mobile voice mailbox server is not "hearing" the audio and it thinks that time has passed without audio and it ends the connection.  I can use my wife's OP 6T with my SIM in it.  So the problem is specific to OP9 5G and specific to T-Mobile, BUT it does not affect ALL OP phones just my OP9 5G.  People can leave me messages, so there is no problem with "my" voice mail.  Something in the software of this specific phone or the T-Mo voicemail server is incompatible with one another.  Keep in mind that with my device I have trouble leaving messages in the voice mailbox of subscribers of all other carriers, so even if my device is involved, so is the T-Mo server.  Temporarily while I find a solution for the OP9 5G, I am using a OP Nord 200 which I don't like much, but it is what I have.