wp_postmeta table not getting updated after migration

I migrated my 6-month old wordpress site from a godaddy legacy server to the deluxe cpanel hosting service. The existing images that were on the site before still load okay, but I cannot see or manipulate any new images via the media library – I don’t get an error message, I see the progress bar as it “uploads” the image, but then I just get a grey box where the image should be. I also cannot add either new (greyed out) images or existing images to new posts using the wordpress editor. If I go in to edit the new images, I can see that the “file name” and “file size” fields are empty (these have names for the older ‘working’ images). However, the url field does contain a link that leads to the uploaded image, which has been uploaded to where I would expect it to be (i.e. in …/wp-content/uploads/2018/08/image.jpg). So the image is getting uploaded, but wordpress won’t generate thumbnails and I can’t use it.

In case it’s relevant, for the migration, I followed godaddy’s procedures to export the database and ftp the files off, then import the database to the new wordpress location and ftp the files up.

As far as I can tell, attachments are being uploaded to the wp_post table (because i can see the new images and resized thumbnails when I check this table), but for some reason the wp_postmeta table is not getting updated at the same time (because I can’t see links to the new images when I check here). This is presumably why I can’t see any new images on the site? But I still don’t know why or how to fix it.

So far I have tried without success
– disabling all the plug-ins
– trying different sizes and sources of images (all <1Mb)
– different browsers
– changing the permissions of the wp-content/uploads folder (set at 755, also tried 777 and 744)
– running the force thumbnail regenerator plug-in
– different PHP versions, as well as increasing the memory limit, post_max_size and upload_max_filesize
– creating a new administrator account
– reinstalling wordpress
– contacting support at the hosting site

I am at a loss regarding what else I can do. Can anyone help identify the issue? Or suggest anything else I can try? Thanks very much in advance!

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