Indestructible blocks and unable to place blocks in certain area (far awar from spawn)

My friend made a server and there is a specific area where the blocks are indestructible and I can't place any blocks on the 2nd day of playing on the server. The area is where my chicken and sheep farm is, I thought that the server lagged because there are too many animals. I tried killing most of the chickens and sheep leaving only 5 sheep and chicken but it didn't fix anything. This area is far from the spawn area and this problem happens to all users in the server.