Images are not uploading on the publish page. They upload successfully only if the image size is less than or equal to 20KB. Anything above 20KB shows an upload failure error with an unknown reason.

my php ini

display_errors = Off
max_execution_time = 2048
max_input_time = 60
max_input_vars = 1000
memory_limit = 128M
post_max_size = 8M
session.gc_maxlifetime = 1440
session.save_path = "/var/cpanel/php/sessions/ea-php82"
upload_max_filesize = 2M
zlib.output_compression = Off

Discuss with hosting provider.
There are 3 different variables in php related to file uploads.