oAuth1 Failing To Provide Signature for Strings With Square Brackets - Error 401

Question

I am obtaining an error when trying to use my oAuth1 signature generator for square bracket endpoints.

1. products/{sku}- Success
2. products?searchCriteria[filterGroups][0][filters][0][field]=sku&searchCriteria[filterGroups][0][filters][0][condition_type]=eq&searchCriteria[filterGroups][0][filters][0][value]={sku} - ERROR

Error Message:

AxiosError: Request failed with status code 401
    at settle (/var/task/node_modules/axios/dist/node/axios.cjs:1261:12)
    at IncomingMessage.handleStreamEnd (/var/task/node_modules/axios/dist/node/axios.cjs:2444:11)
    at IncomingMessage.emit (node:events:539:35)
    at endReadableNT (node:internal/streams/readable:1345:12)
    at processTicksAndRejections (node:internal/process/task_queues:83:21) {
  code: 'ERR_BAD_REQUEST',

At the bottom of the cloudwatch log: data: { message: 'The signature is invalid. Verify and try again.' }

How do I encode square brackets to create the correct signature?