How do I Fix Armour Stands & Item Frames Despawning?

Hi! I'm pretty new to this whole 'making a thread' thing, so please bare with me!

I was building on my Aternos server when I made something that required items on an armour stand (a dragon head and chainmail helmet) and an item frame with a quartz slab inside of it. I think these things class as entities, so is there a way to turn off entities despawning or stop this from happening? It's just a little annoying.

Thank you!

Hm, really? That's odd. Is there anything that you could suggest? Does it seem like a simple fix where I could just re-log or something?

Hm, I do have a few plugins installed. I'll have to play around with them and take some out. Thank you!