Textures Missing

I play on a realms server with addons. Both textures from the Pets+ Addon and some vanilla textures are missing or glitched while playing. Vanilla ones I’ve noticed are the clock item, it is a solid yellow square, and sometimes the armor, health, and hunger bars, are glitched almost solid colored squares but I believe they were faded a little at the edges. In the Pets+ Addon, some mobs were a solid color, others were invisible excluding their shadow.