One way sound issue with OPUS codec, but not with other codecs

When using the OPUS codec in FreePBX 14. with asterisk 14, I have one way audio where one side or one party can hear the other, but not reverse. Using other codes like G722 gives perfect two-way audio. Any ideas ?

Try using another SIP phone. I’ve seen this with Blink for example, but other SIP phones work. PhonerLite is a great SIP softphone for testing.