Blockchain Witness Requests Failing

[ehusar]

Hopefully I am posing this isn the right place. I have been having witnesses request failing off and on for about 36 hours now . It is hit and miss and I've tested multiple random addresses. Sometimes it replies with 'Internal Server Error' which is response 503 I believe and other times is is the "Too Busy" reply. Is this a known issue?

Thanks in advance.