Error message after upgrade

Sorry I’m new to this.

I posted that I couldn’t send messages without getting an error but I cant find the post.

I consulted with the guru at my isp and I went to settings and upgraded my passwordon the outbound server.

I was then able to send messages but still got the error: " Failed to send some messages.server only accepting messages from authenticated sources".

But then I would spontaneously periodically get the same error message.

I figured that it was the same periodicity as my fetchcycle.

I went to settings and upped my fetch frequency.

the messages ceased unless I forced an update.

I have a Motorola X3 upgraded to the highest Android.

I Have the latest and greatest K9.