asterisk users - Dec 2014 - Operating with different codecs - can't native bridge...

When I try to dial out I get an error: 
Operating with different codecs [0x2 (gsm)] [0x4 (ulaw)] , can't native
bridge..


Here are the details:

   -- Accepting AUTHENTICATED call from 66.18.210.217:
       > requested format = gsm,
       > requested prefs = (),
       > actual format = gsm,
       > host prefs = (gsm|ilbc|ulaw|alaw|speex),
       > priority = mine
    -- Executing [1800847xxxx at iax_zoiper_kathy:1]
Macro("IAX2/zoiper_kathy_old_phone-2047",
"tollfree,1800847xxxxx") in new stack
    -- Executing [s at macro-tollfree:1]
Dial("IAX2/zoiper_kathy_old_phone-2047", "IAX2/xxxx at
voip/180084777xx,150,tr") in new stack
    -- Called IAX2/xxxxxx at voip/1800847777x
    -- Call accepted by 184.75.215.114 (format ulaw)
    -- Format for call is ulaw
    -- IAX2/voip-2745 is making progress passing it to
IAX2/zoiper_kathy_old_phone-2047
    -- IAX2/voip-2745 answered IAX2/zoiper_kathy_old_phone-2047
    -- Operating with different codecs [0x2 (gsm)] [0x4 (ulaw)] , can't
native bridge...
    -- Operating with different codecs [0x2 (gsm)] [0x4 (ulaw)] , can't
native bridge...

Is is it possible to make it to work besides switching to "ulaw"

-- 
Joseph