Learn more about this change here.
For help regarding Aternos, we recommend you to visit our support center.
I'm sorry but I've tried it several times but I can not put the server log here so it's in that file
Before opening the server I uploaded my world of 44.4 MB. After this start the server and wait for the account. At the end, the server began to load and I started to start but shortly after I could enter but that was still in the beginning. After this the server closed.
I have the custom npc's mod.
Thanks for helping
The problem seems to be caused by your map as it needs to be upgraded to the newest version of the mod.
Please try to start this map with your client and upload it again.
Hello Roman. Thanks for helping.
But I did what you told me.
And the same happened ...
I leave the server log in a file. In case you want to come back to help me ...
EDIT: Thanks, but I've fixed it.
Grab a world generated by the server.
And I put the things of the world (4.44MB) with mcedit.
And I start.
But thanks for helping me. 
