If off, is it only the one service where you are getting this error? Are other Azure Maps services working for you? If they others are working, double check that the subscription keys are the same (easy to clip off a character or two when copy/pasting).
As you mentioned, looking in your Azure subscription to see if you can locate the Azure Maps resource. Since 2018/2019 there was a new pricing structure that went out called "Gen2". However, Gen1 pricing is not planned to be retired until 2026 as documented here: https://learn.microsoft.com/en-us/azure/azure-maps/how-to-manage-pricing-tier So that shouldn't be the issue. If you do find the subscription, you will want to go into the pricing tier and update it to use Gen2 before that retirement date.
If you can't find the Azure Maps resource in your teams/companies Azure Subscription, its possible that someone within your team/company accidentally deleted the resource. In that case, simply create a new Azure Maps resource in your subscription, retrieve a new shared key or consider one of the increased security auth options. Here are some related docs: