Can't receive faxes after switching to g729: Dropping incompatible voice frame on of format ulaw since our nativ

Can’t receive faxes after switching to g729

The log gives the message:
[2013-02-26 13:55:08] NOTICE[5915] channel.c: Dropping incompatible voice frame on SIP/110-00022de6 of format ulaw since our native format has changed to 0x100 (g729)

I have g729 as the primary codec, and ulaw as a secondary.

Any ideas on how to fix this?

TIA