Unable to export – Out of disk space. Unable to write content to file.

All-in-one wp migration Error pop up:

Out of disk space. Unable to write content to file. File: /opt/bitnami/apps/wordpress/htdocs/wp-content/plugins/all-in-one-wp-migration/storage/pkzo3q9y7sf0/ec2-34-211-155-226.us-west-2.compute.amazonaws.com-20210414-044007-8meggr.wpress

Disk space is not the issue though:
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 197G 9.1G 178G 5% /
udev 780M 12K 780M 1% /dev
tmpfs 158M 168K 157M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 786M 0 786M 0% /run/shm
/dev/xvda3 335G 195M 318G 1% /mnt

Error log:

This is the only error i see.

Apr 14 2021 17:43:50
{“type”:2,”message”:”call_user_func_array() expects parameter 1 to be a valid callback, class ‘Css_class’ does not have a method ‘register_settings_and_fields'”,”file”:”\/opt\/bitnami\/apps\/wordpress\/htdocs\/wp-includes\/class-wp-hook.php”,”line”:286}

Permissions:
Out of frustration i set all wp-content to 777

It worked once with the most minimum export. But now even that export will not work. Any help will be appreciated. Thanks!