You know the score. You set up a maintenance plan to backup all or most of your databases on an instance then you get an email saying the job has failed. Doesn’t mean they all didn’t backed up . . . Get a list of the last backup for every database in your instance, backup only the one which failed to backup.

Change the type of backup to ‘D’ to get the last full and ‘I’ to get the last differential

select bs. database_name, bs .type, max( bs. backup_finish_date ) AS Latest_bak
from sys .databases as d
left join msdb.dbo.backupset as bs
on d. name = bs .database_name
where is_copy_only = 0 and type = 'D'
group by database_name, type
order by database_name