I have a feeling they're having some server issues. Spoke to the guys at Scrapebox and showed them my error messages. They were thinking it's probably server issues or banned IPs. Hmm..
I'm from Storm Proxies and I can confirm that there are no server issues on our side.
Only way to resolve issue is by contacting our support team.
Yeah good advice there. I'll try that.
I am facing 503's too with storm proxies occasionally.