How Do I Overcome Time Machine Backup Failure?

Last fall I bought a Seagate 5TB Backup Plus (brand recommended on your site). It backed up my MBP 2013 once and ever since every attempt gives me a failure message “Time Machine couldn’t complete the backup to “Seagate Backup” or the other message same thing “MBP Backup”. I am currently using Mojave 10.14.4 and believe I was using Mojave when I did the first backup. I have run disk utility and repair multiple times but still not able to complete the backup. Can I erase the Seagate and start from scratch? If so where do I find the instructions for that?
Many thanks,
Christol
PS: I learn so much from your videos
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Christol