@edgarblythe,
sometimes there are technical reasons (unintended) for such scenarios. However, with all of these new-fangled ways to contract one another, there are also new potential ways to get feathers ruffled and/or have these slights. sometimes it's with people who you don't really know their emotional situation.
In one case, I have a formerly VERY close friend of mine of 45 years who/whom I see log onto Skype every day. We had at one time used Skype a few times to chat but now...we haven't been in touch in over 10 months. The contact has been sputtering for the last few years but at one point we got together weekly for 25-30 yr.
I don't even know why that is happening because we never had a an angry word...or disagreement. I've a choice... I could say, '**** happens' or simply call him ..on the phone.