How to join with friend?

This is for Arcane Legends.

I clicked on Social, then in Friends tab I clicked on my friend "Party Invite". My friend then accepted the invite. On my Party tab I see my friend but not a "join" or "go to" option.

I went back to the battle screen click on my friend's name, the popup menu has the join disabled. I sent another invite, and again he accepted. Still no option to "join" or "go to".

In hopes to solve this problem I bought some platinum and created a guild. When I go to Social, and click on the guild tab the "Party Invite" is disabled.

I want join up with my friends so we can team up and complete quests together. What am I doing wrong? What am I missing? This is frustrating.

Sometimes I see, "can't join in full game". What does that mean? We have tired to join each other in towns, forest and mines.

I searched this issue on the forms, and the answer seems to be the portals/servers/instances (whatever they are called) are full. So, is this what I can expect in this game? If I'm lucky I might be able to join my friends? If it is a server full issue, then when is the least crowded time? Should we try at 3:00 AM on a Tuesday morning to see if we have better luck to join with each other?

Sometimes, when there is a Join button, and "Can't join in full game" pops up, it means that when you clicked the button, there was a spot in that map for a player, but another player probably joined that map before you did, therefore, giving you the "cannot join a full game" message. (At least, this is how i think this is what happens)

When there is NO join button, it means that the map is already full and cannot hold any more players (if its a town)
if its a campaign map, that either means that the map is already full, or if its an event map, someone is already attacking the boss so no one else can join


hope that helps