It's not just you - Dark Souls 3 summoning is a bit broken at the moment
Dark Souls has always been a game filled with glitches. There’s a reason that speed runners are divided into glitch-users and glitch-free play throughs. Glitches can be used to beat bosses more easily, maneuver environments or generally make life easier. However, sometimes the glitches are just a sign of problems in the game that need fixing, and summoning issues fall into that category.
I noticed some bad summoning issues with my other half was playing Dark Souls 3 on PS4 this weekend. Sometimes it would work the way it’s supposed to – he could get summoned into other players’ worlds to help with a boss battle, or summon in the help of a Sun Bro if he wanted. Other times, it simply didn’t work. He would put down his summon sign and the animation would show but the summon sign wouldn’t appear. Or it would appear but he couldn’t be summoned. Or he would try to summon and it kept saying unable to summon phantom. Sometimes, the game would crash while attempting to summon or be summoned.
As usual for South Africans, I assumed it was an issue with our internet. That is, until I went looking to see if other people were having the issue. There were a bunch of reddit threads and steam community posts with similar issues, but my favorite was this YouTube video. I’m not embedding it because of game spoilers, but if you aren’t avoiding spoilers it shows off a bunch of issues experienced with summoning. From bosses not showing animations, thereby making players invincible, to being unable to access boss arenas, to simply being unable to summon anyone, it seems that summoning is rather broken at the moment.
I have faith in From Software that this will be fixed soon. The unique approach to multiplayer and coop is a hallmark of these games, and adds so much to the experience. I’m sure they are working on a fix as I write this, but for now, don’t stress – it’s not you, it’s Dark Souls.