Looks like I’m in the same boat…
root@ee:~# apt upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
mysql-common
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 8,490 B of archives.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] Y
Err:1 http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.1/ubuntu xenial/main i386 mysql-common all 10.1.15+maria-1~xenial
404 Not Found [IP: 198.199.99.226 80]
Err:1 http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.1/ubuntu xenial/main i386 mysql-common all 10.1.15+maria-1~xenial
404 Not Found [IP: 198.199.99.226 80]
E: Failed to fetch http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.1/ubuntu/pool/main/m/mariadb-10.1/mysql-common_10.1.15+maria-1~xenial_all.deb 404 Not Found [IP: 198.199.99.226 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?