neather portal not spawning

when i build a portal form the overworld to the neather when i enter the portal i get a normal loading screen but when it loads a solid color screen comes up and theres nothing but be floating around the solid color area, i save and exit then it loads normally but no portal is found anywhere near me where i entred the neather. when i build a portal in the neather to get back to the overworld it loaded normally but when it loaded i was floating wiith no land anywhere but sky box everyhere so i save and exit the game. when i re loadede it, it loadede normally but there was no portal again but instad of puting me near my orginal portal it put me about 25-30 chunks away form the place i was supposed to spawn.