[Help] Video quality

[Soundburst]

Hello! I have a serious problem. I render all my videos in Sony Pro Vegas with the same output format. In recent days, all my newest videos uploads on youtube with low video and thumbnail quality (On phone I can watch those videos only in 240p and I can't change to HD). I have tryed to change output formats, I've even used After effects. What's happening?

P.S. Some of my videos uploads fine.

 

[Kath]

To get the best help, I'll move this here for you

 

[Jawad Soomro]

I dont think any of your past or newer videos got any lower quality problem,they're cool, wow u Haunted song is so awesome!! Rapper is mindblowing I love rapping too

 

[Soundburst]

I dont think any of your past or newer videos got any lower quality problem,they're cool

I delete all bad quality videos! Luckily I have left one.

Fable - Killing Our Memories (Thumbnail Quality: Good; Video Quality on PC: More Than Good; Video Quality on Phone: Good)

Witt Lowry - Lay Here (Thumbnail Quality: Bad; Video Quality on PC: Good; Video Quality on Phone: Bad - 240p lock)