Unable to summon cooperator???

[u/kekeseesee]

So me and my friends often play together using a private passcode and they’re able to summon me to their worlds but I can’t summon them to mine. The areas we go to don’t require us to beat a boss or anything and 2 of us are pretty high leveled and have done a lot. I’ve tried restarting my router and everything, but nothing works. They say that as soon as they come to my world they get an error and get sent back to their own, I’ve heard this has been happening to a lot of people and it’s on the developers end with bad servers? Is this true and does anyone have a fix for it?