[SipML5] fingerprint sha-256 failed to create fingerprint

i’m using asterisk 11.12 with sipml5 and the last version of chrome. I have to setting in sip.conf for every sip user these parameter :
But when i try to call i have this problem on chrome console :
Failed to parse Sessiondescription. a=fingerprint:sha-256 failed to create fingerprint from digest.
How can i resolve it ?
Reading on the web, the solution would seem to be to install certificate on asterisk.
If this is the solution, how can add this certificate on asterisk ?
Thanks for the support