Can't call to another SIP server Says " our cricuits busy now call later"

I need to send calls to another sip server but its says " our cricuits busy now call later" it was working before, we have Trunk created between your SIP severs it seems somting with Trunk is not working.

in the FreePBX System Status shows this message:
14 extensions/trunks have weak secrets
Warning: The use of weak SIP/IAX passwords can compromise this system resulting in toll theft of your telephony service. You should change the reported devices and trunks to use strong secrets.

Extension: XXX / Secret less than 6 digits
Extension: XXX / Secret less than 6 digits

Please kindly some one help me in this…

Thank you