Media Library not uploading all photos: HTTP error

`Hi,

I’m quite new to wordpress and am having issues uploading photos to my media library for my travel blog: https://www.butternutbutts.com. For around every 20 photos I try to upload, only 1 or 2 will actually upload, the others come up with the ‘HTTP error’ message. My site is hosted by bluehost and I’m using one of the free wordpress themes.

So far I have tried (and none of these have worked):
1) upgrading to the latest version of wordpress, twice
2) de-activating all plugins and re-activating them one by one
3) bulk/drop-and-drag/individual photo upload methods
4) waiting 2 days to see if the problem sorted itself

All my plugins are up to date, and I haven’t run out of disk space storage either.

I don’t know anything about coding so if there’s something I need to change in the HTML code please explain it really simply! Thank you so much for your help.