Getting 502 backend error

its been one hour i am getting 502 backend error frequently. there was no changes in the code. Suddenly I am receiving 499 error and when i am trying to reload webapp many time its giving 502 backend error. below are my site address

Hi there, one of the servers you were on was near maximum capacity for a while earlier, but the load has been rebalanced now. Let us know if things are back to normal?

It seems everything is normal now. thank you