If the node is new, it’s being vetted. This period is there to ensure your node is “worthy” of the network, or should I say “healthy”.
As this stage, I think it’s actually a good thing if it fails and gets suspended quickly so the SNO can investigate and figure out a fix before the node joins the network for good.
Nodes usually don’t get suspended after one or two issues. My nodes can fail 10+ audits before being in (serious) trouble. But the younger a node, the more it gets affected by online failures.
Besides, your node did not precisely fail audits otherwise its Audit score would have dropped, instead an unknown error occurred during an audit. So it got suspended to let you know you need to fix it (during a limited time window) before it is allowed to go again.
With regards to the precise issue you’re facing (unable to get signee), personally I’m not sure what it means. The only kinda related thread I could find is the following, where @Alexey suggests a possible network issue:
Someone else than me might know better.