Compilation error: Exception occurred on the metadata service

Hi

Anyone can help me. I’m compiling my project made, when I’m waiting to finish errors appeared that

"Exception occurred on the metadata service on client or server. See exception details below:

Unable to log on to Microsoft Dynamics AX."

See pic below message. TIA

What element are you compiling? An SSRS report? I assume it’s AX 2012 (please attach a tag with the version next time).
Did it work before? If not, what has changed? Did you try to restart the AOS?