This error could happen because of an SSL misconfiguration.
To try and fix it you could check cloudflare SSL settings:
In cloudflare set SSL to Full or Full (strict) (not Flexible), as Flexible SSL can cause redirect loops if your server is already configured for HTTPS.
or try to bypass cloudflare temporarily by disabling the Cloudflare proxy (the orange cloud) for webmail.solcomissaria.com.br.
It seems like it could be an issue with your server, not necessarily with cloudflare.
And remember to clear your browser’s cache and cookies, as old redirects may still be cached.