Sometimes invidious instances can become obsolete. To update the feed and site urls in miniflux,
execute the following commands:

sudo -iu postgres
psql -d miniflux

update feeds set feed_url = replace(feed_url,'https://invidious.snopyta.org/','https://invidious.sethforprivacy.com/') where feed_url like 'https://invidious.snopyta.org/%';
update feeds set site_url = replace(site_url,'https://invidious.snopyta.org/','https://invidious.sethforprivacy.com/') where site_url like 'https://invidious.snopyta.org/%';