Getting this message when trying to login?:

Unable to connect to Indian Railways server. Please retry.

It clearly means that IRCTC has received your request but currently unable to process it.

Then it can be due to following reasons:

• IRCTC server/service closed deliberately or by accident or during unscheduled maintenance
• Server crash
• Network lines down within IRCTC

These are not the causes

• Your computer/browser or internet problems
• Railway server which actually handles booking/cancellation down is less likely

What to do?

Keep retrying...