I have had the same issue as Aleet for about a year.
For me its intermittent. I may go weeks with no issues making outgoing calls and then I will have days where a high percentage of outgoing calls result in white noise when the person I am calling picks up. I will call multiple times in a row with the same result. (I can call someone else in-between attempts without this issue). Try the problem number again and get white noise again. If the person I am calling gets annoyed and calls me back, the call connects fine without issue. If they don't call me back and I grab my Verizon cell phone (bypassing obi and GV) the call goes though without issue... so I only have the issue on the Obi. On other days I can call the same number using my obi and not have any issue at all. (To be clear its not just one number I am having the issue with. On bad days its a large percentage of outgoing calls to multiple numbers yet other numbers work fine)
Obi replaced my obi200, obi support reconfigured it several times and I still have the same intermittent issue. When I am having the issue, I have restarted my Asus router and my ob200 and it doesn't make a difference. I have tried using corded phones and cordless phones connected to the Obi200 and both have the same issue.
Currently running obi200 w/ 3.2.2 (Build: 5921EX) and having this issue again today. Nothing today has changed at my end since working fine yesterday. My internet connecting with xfinity is working fine today as it is most days. I have the same devices on at my location as other days.... but today for some reason I get white noise when the person I am calling picks up. Some numbers I call are fine. Some numbers I call who have xfinity phone service are fine. Other people I have tried multiple times and all I get is white noise. That same person I called without issue yesterday using my obi and I can not call them now using obi but can using my cellular service. Based on my obi200's historical performance over the past year, I will likely be able to call that same person again in the next few days without making a change to anything at my end. I just don't know when that will be.
I hope to see a fix soon that works for everyone.