When i play singleplayer on my world creatures are lvl 50+ but if i invite my friend by LAN creatures are lvl 1 all the time. How can i change that and have high level of creatures on multiplayer?

Did you edit the config? If so, show me your edited lines

Yes i edited it:
"increasingDistance": 2000,
"distanceFactor": 0.75,
"increasingTime": 30,
"timeFactor": 0.1,
"heightDistance": 50,
"heightFactor": 0.05,
"maxFactorHealth": 9.55,
"maxFactorDamage": 7.0,
"maxFactorProtection": 10.0,
"maxFactorSpeed": 2.0,
"allowRandomValues": false,
"randomChance": 10,
"randomFactor": 10,
"extraXp": true,
"maxXPFactor": 5.0,
"startingFactor": 1.0,
"startingDistance": 0,
"startingTime": 0,
"startingHeight": 62,
"positiveHeightIncreasion": true,
"negativeHeightIncreasion": true,
"affectBosses": true,
"excludeDistanceInOtherDimension": true,
"excludeTimeInOtherDimension": true,
"excludeHeightInOtherDimension": true,
"dropMoreLoot": true,
"moreLootChance": 0.02,
"maxLootChance": 0.7,
"chanceForEachItem": 0.5,
"levelZLevelFactor": 0.0,
"levelZPlayerRadius": 0.0,
"hudTesting": false,
"excludedEntity": [],
"allowSpecialZombie": true,
"bigZombieChance": 10,
"bigZombieSlownessFactor": 0.7,
"bigZombieBonusLifePoints": 150,
"bigZombieBonusDamage": 30,
"bigZombieSize": 1.5,
"speedZombieChance": 10,
"speedZombieSpeedFactor": 1.5,
"speedZombieMalusLifePoints": 10,
"dynamicBossModification": true,
"dynamicBossModificator": 0.5,
"bossMaxFactor": 5.0,
"bossDistanceFactor": 0.05,
"bossTimeFactor": 0.0,
"creeperExplosionFactor": 2.0
}

Mh looks good, not sure why it is not working correctly

Come to my discord.