TFTP Server Not Transferring Data

I am trying to flash firmware to a Yealink SIP-T46G IP phone using TFTPD32 which I’ve used a lot for Cisco phone and it’s worked well. So I point the phone to the IP of the TFTP server, and it starts trying to pull the first file. However, the progress bar on the window that pops up on TFTPD32 usually starts moving and doesn’t stay at “O bytes”. I’ve tried rebooting the computer and stuff and wiresharking it. It’s obviously communicating with the TFTP server trying to pull files, but it’s like it can’t make and progress. It just keeps trying with new ones over and over again. Here’s what the wire shark says:

TFTP 81 Read Request, File: T46.rom, Transfer type: octet, timeout=5, blksize=1468 TFTP 67 Option Acknowledgement, timeout=5, blksize=1468 TFTP 67 Option Acknowledgement, timeout=5, blksize=1468

Some time passes

TFTP 67 Error Code, Code: Not defined, Message: Undefined error code TFTP 67 Error Code, Code: Not defined, Message: Undefined error code

And this repeats infinitely. Thoughts? Thanks!