Insufficient resources on 3G data users, but no congestion in KPI

Hello.

ESM Cause insufficient resources (26) On 3g data users.
But when I check KPI there is no resource congestion.

Any comments?

Is ESM a RAN message?
Can you make a snapshot of the message?

No.
Customer is on 3G, they have been complaining of poor data service but are very close to site.