UnityWebRequest Timeouts (some times) but postman success (always)

We have a published game with +50k active users.

we are using unity WebRequest to get configs from our server, I noticed on the hours of day that requests to our server are high, we encounter a lot of timeouts on one of our post requests.

I narrowed it and saw in traffic hours, that post request gets to time out in unity, while in the same time the PostMan software, can fetch the data and succeed.

Maybe worth mentioning that by putting breakpoints in mine unity scripts, I saw, while a timeout is happened, the request.downloadhandler.text contains the server answer json, but it's not complete. Also I should mention that we haven't set unityWebRequest.Timeout property, though setting it to a large number even didn't help.

I wanted to ask what do you think is the difference between PostMan and unityWebRequest, that the postman success, while unity can't?

Do you think migrating to C# http request would help?

Thanks.