Don't use Scaleway for self-hosted email
I've been using Scaleway for my personal email server for almost 18 months now, and sending email has been troublesome almost from the start, with issues that Scaleway support apparently doesn't understand or, if they do understand, are unable to fix. Both are related to the netblock that my IPs are assigned from.
For the first server, which runs a private mailing list, the entire /23 that it is a part of is listed as part of the Spamhaus RBL. Scaleway seems unwilling or unable to remove it as the relevant ticket has been open for eight months.
For the second server, which runs my primary email domain, the netblock from which Scaleway assigns IPs is apparently marked as DUN, i.e. dynamically-assigned IP addresses assigned to Internet users connecting via non-permanent connections such as ADSL. Many mail hosts, including quite important ones like Gmail and Hotmail, correspondingly spamfilter the entire netblock.
Scaleway is unable to remedy this situation. Support has been attentive but incompetent.
Update, late November: Scaleway has now managed to remedy the second problem, but not the first.