Pinterest bot detected on Private Proxy

Hello everyone,
I am running a bot written on Imacros under Firefox profile, which uses a private proxy.
I have got 10 proxies on 10 different profiles. On some of them I can't even login. I receive the following message (by analyzing a connection):
Uh oh! We've found a bot. It looks like there's a bot running on your network. Send us a message with your IP address and we'll help you get going again.

On the screen browser tries to connect several times and then I receive the message on the page:
[h=1]Error 503 Service Unavailable[/h] Service Unavailable
[h=3]Guru Meditation:[/h] XID: 974442499
Varnish cache server

I believe this happens because IP is blacklisted.
Should I ask proxy provider to replace the proxy or wait 24 hours or what to do?
Please help if anyone has faced such an issue.
Thank you!

Maybe this will be useful for someone, I have replaced proxies and everything works properly now.
So Pinterest just blocked an IP address, so make sure your proxies are not ghosted or you will have to replace them otherwise.
Thanks everyone.

99.9% of the time it's the proxy
You won't believe the amount of ips they have on file which are blacklisted !

Ips are blocked for sure.