Actually, after further investigating my netlify site dashboard, I found the log for the function on my dev branch. Here is the error message from the log:
(it seems like an axios error, but not sure why that would be the case since the axios call works for me locally)
9:24:56 AM: 2020-02-16T14:24:56.578Z c11ec822-0321-47db-adc7-fec51e612690 INFO Error: Request failed with status code 404 at createError (/var/task/node_modules/axios/lib/core/createError.js:16:15) at settle (/var/task/node_modules/axios/lib/core/settle.js:17:12) at IncomingMessage.handleStreamEnd (/var/task/node_modules/axios/lib/adapters/http.js:237:11) at IncomingMessage.emit (events.js:228:7) at endReadableNT (_stream_readable.js:1185:12) at processTicksAndRejections (internal/process/task_queues.js:81:21) { config: { url: 'https://api.netlify.com/build_hooks/5e49370b645e93bc77b1e743?trigger_branch=render-comments&trigger_title=triggered+by+submission-created+build+hook', method: 'post', data: '{}', headers: { Accept: 'application/json, text/plain, */*', 'Content-Type': 'application/json;charset=utf-8', 'User-Agent': 'axios/0.19.0', 'Content-Length': 2 }, transformRequest: [ [Function: transformRequest] ], transformResponse: [ [Function: transformResponse] ], timeout: 0, adapter: [Function: httpAdapter], xsrfCookieName: 'XSRF-TOKEN', xsrfHeaderName: 'X-XSRF-TOKEN', maxContentLength: -1, validateStatus: [Function: validateStatus] }, request: ClientRequest { _events: [Object: null prototype] { socket: [Function], abort: [Function], aborted: [Function], error: [Function], timeout: [Function], prefinish: [Function: requestOnPrefinish] }, _eventsCount: 6, _maxListeners: undefined, outputData: [], outputSize: 0, writable: true, _last: true, chunkedEncoding: false, shouldKeepAlive: false, useChunkedEncodingByDefault: true, sendDate: false, _removedConnection: false, _removedContLen: false, _removedTE: false, _contentLength: null, _hasBody: true, _trailer: '', finished: true, _headerSent: true, socket: TLSSocket { _tlsOptions: [Object], _secureEstablished: true, _securePending: false, _newSessionPending: false, _controlReleased: true, _SNICallback: null, servername: 'api.netlify.com', alpnProtocol: false, authorized: true, authorizationError: null, encrypted: true, _events: [Object: null prototype], _eventsCount: 9, connecting: false, _hadError: false, _parent: null, _host: 'api.netlify.com', _readableState: [ReadableState], readable: true, _maxListeners: undefined, _writableState: [WritableState], writable: false, allowHalfOpen: false, _sockname: null, _pendingData: null, _pendingEncoding: '', server: undefined, _server: null, ssl: [TLSWrap], _requestCert: true, _rejectUnauthorized: true, parser: null, _httpMessage: [Circular], [Symbol(res)]: [TLSWrap], [Symbol(asyncId)]: 5, [Symbol(kHandle)]: [TLSWrap], [Symbol(lastWriteQueueSize)]: 0, [Symbol(timeout)]: null, [Symbol(kBuffer)]: null, [Symbol(kBufferCb)]: null, [Symbol(kBufferGen)]: null, [Symbol(kBytesRead)]: 0, [Symbol(kBytesWritten)]: 0, [Symbol(connect-options)]: [Object] }, connection: TLSSocket { _tlsOptions: [Object], _secureEstablished: true, _securePending: false, _newSessionPending: false, _controlReleased: true, _SNICallback: null, servername: 'api.netlify.com', alpnProtocol: false, authorized: true, authorizationError: null, encrypted: true, _events: [Object: null prototype], _eventsCount: 9, connecting: false, _hadError: false, _parent: null, _host: 'api.netlify.com', _readableState: [ReadableState], readable: true, _maxListeners: undefined, _writableState: [WritableState], writable: false, allowHalfOpen: false, _sockname: null, _pendingData: null, _pendingEncoding: '', server: undefined, _server: null, ssl: [TLSWrap], _requestCert: true, _rejectUnauthorized: true, parser: null, _httpMessage: [Circular], [Symbol(res)]: [TLSWrap], [Symbol(asyncId)]: 5, [Symbol(kHandle)]: [TLSWrap], [Symbol(lastWriteQueueSize)]: 0, [Symbol(timeout)]: null, [Symbol(kBuffer)]: null, [Symbol(kBufferCb)]: null, [Symbol(kBufferGen)]: null, [Symbol(kBytesRead)]: 0, [Symbol(kBytesWritten)]: 0, [Symbol(connect-options)]: [Object] }, _header: 'POST /build_hooks/5e49370b645e93bc77b1e743?trigger_branch=render-comments&trigger_title=triggered+by+submission-created+build+hook HTTP/1.1\r\n' + 'Accept: application/json, text/plain, */*\r\n' + 'Content-Type: application/json;charset=utf-8\r\n' + 'User-Agent: axios/0.19.0\r\n' + 'Content-Length: 2\r\n' + 'Host: api.netlify.com\r\n' + 'Connection: close\r\n' + '\r\n', _onPendingData: [Function: noopPendingOutput], agent: Agent { _events: [Object: null prototype], _eventsCount: 1, _maxListeners: undefined, defaultPort: 443, protocol: 'https:', options: [Object], requests: {}, sockets: [Object], freeSockets: {}, keepAliveMsecs: 1000, keepAlive: false, maxSockets: Infinity, maxFreeSockets: 256, maxCachedSessions: 100, _sessionCache: [Object] }, socketPath: undefined, method: 'POST', path: '/build_hooks/5e49370b645e93bc77b1e743?trigger_branch=render-comments&trigger_title=triggered+by+submission-created+build+hook', _ended: true, res: IncomingMessage { _readableState: [ReadableState], readable: false, _events: [Object: null prototype], _eventsCount: 3, _maxListeners: undefined, socket: [TLSSocket], connection: [TLSSocket], httpVersionMajor: 1, httpVersionMinor: 1, httpVersion: '1.1', complete: true, headers: [Object], rawHeaders: [Array], trailers: {}, rawTrailers: [], aborted: false, upgrade: false, url: '', method: null, statusCode: 404, statusMessage: 'Not Found', client: [TLSSocket], _consuming: false, _dumped: false, req: [Circular], responseUrl: 'https://api.netlify.com/build_hooks/5e49370b645e93bc77b1e743?trigger_branch=render-comments&trigger_title=triggered+by+submission-created+build+hook', redirects: [] }, aborted: false, timeoutCb: null, upgradeOrConnect: false, parser: null, maxHeadersCount: null, _redirectable: Writable { _writableState: [WritableState], writable: true, _events: [Object: null prototype], _eventsCount: 2, _maxListeners: undefined, _options: [Object], _redirectCount: 0, _redirects: [], _requestBodyLength: 2, _requestBodyBuffers: [], _onNativeResponse: [Function], _currentRequest: [Circular], _currentUrl: 'https://api.netlify.com/build_hooks/5e49370b645e93bc77b1e743?trigger_branch=render-comments&trigger_title=triggered+by+submission-created+build+hook' }, [Symbol(kNeedDrain)]: false, [Symbol(isCorked)]: false, [Symbol(kOutHeaders)]: [Object: null prototype] { accept: [Array], 'content-type': [Array], 'user-agent': [Array], 'content-length': [Array], host: [Array] } }, response: { status: 404, statusText: 'Not Found', headers: { 'cache-control': 'no-cache', 'content-type': 'text/plain; charset=utf-8', date: 'Sun, 16 Feb 2020 14:24:56 GMT', 'strict-transport-security': 'max-age=31536000', vary: 'Origin', 'x-content-type-options': 'nosniff', 'x-frame-options': 'ALLOWALL', 'x-nf-srv-version': 'b16237a0ff2b3bf7915250067f95ce0806b166fa', 'x-request-id': 'e6bc1bad-e9b7-4ec7-b094-f0f07230682a', 'x-runtime': '0.008714', 'content-length': '14', via: '1.1 google', 'alt-svc': 'clear', connection: 'close' }, config: { url: 'https://api.netlify.com/build_hooks/5e49370b645e93bc77b1e743?trigger_branch=render-comments&trigger_title=triggered+by+submission-created+build+hook', method: 'post', data: '{}', headers: [Object], transformRequest: [Array], transformResponse: [Array], timeout: 0, adapter: [Function: httpAdapter], xsrfCookieName: 'XSRF-TOKEN', xsrfHeaderName: 'X-XSRF-TOKEN', maxContentLength: -1, validateStatus: [Function: validateStatus] }, request: ClientRequest { _events: [Object: null prototype], _eventsCount: 6, _maxListeners: undefined, outputData: [], outputSize: 0, writable: true, _last: true, chunkedEncoding: false, shouldKeepAlive: false, useChunkedEncodingByDefault: true, sendDate: false, _removedConnection: false, _removedContLen: false, _removedTE: false, _contentLength: null, _hasBody: true, _trailer: '', finished: true, _headerSent: true, socket: [TLSSocket], connection: [TLSSocket], _header: 'POST /build_hooks/5e49370b645e93bc77b1e743?trigger_branch=render-comments&trigger_title=triggered+by+submission-created+build+hook HTTP/1.1\r\n' + 'Accept: application/json, text/plain, */*\r\n' + 'Content-Type: application/json;charset=utf-8\r\n' + 'User-Agent: axios/0.19.0\r\n' + 'Content-Length: 2\r\n' + 'Host: api.netlify.com\r\n' + 'Connection: close\r\n' + '\r\n', _onPendingData: [Function: noopPendingOutput], agent: [Agent], socketPath: undefined, method: 'POST', path: '/build_hooks/5e49370b645e93bc77b1e743?trigger_branch=render-comments&trigger_title=triggered+by+submission-created+build+hook', _ended: true, res: [IncomingMessage], aborted: false, timeoutCb: null, upgradeOrConnect: false, parser: null, maxHeadersCount: null, _redirectable: [Writable], [Symbol(kNeedDrain)]: false, [Symbol(isCorked)]: false, [Symbol(kOutHeaders)]: [Object: null prototype] }, data: 'Page not found' }, isAxiosError: true, toJSON: [Function]}
9:24:56 AM: Duration: 105.00 ms Memory Usage: 80 MB Init Duration: 155.58 ms