Proxies are essential when using GSA Search Engine Ranker to submit backlinks to avoid problems with your server IP address. Shared or dedicated proxies can be bought from SolidSEOVPS.com, there’s a lot of different proxy providers but I’ve been using SolidSEOVPS for years now and can highly recommend them.
They have quick support and haven’t run into any major problems with them. Support tickets are usually answered same day so if for some reason you’re having trouble just shoot them a message through their site.
Simply copy and paste your proxies after payment into GSA SER in the Options menu. Make sure to test them before starting your campaign.
They also have VPS services that are low-cost and reliable for running GSA SER and SEO related tools. I currently use a dedicated server from OVH.com but before that I use their VPS for years without trouble.