500 error from Server on Auth Callback from B2C

Using Azure AD B2C as an auth provider, I receive a 500 error upon callback. There are no logs (I do not use Functions). How can you debug with no server logs? My staticwebapp.conig.json is below.
The url response is of the form "../.auth/login/AzureB2C/callback?state=%2f.auth%2fcomplete&code=eyJraW....."

`{
"auth": {
"identityProviders": {
"customOpenIdConnectProviders": {
"AzureB2C": {
"registration": {
"clientIdSettingName": "",
"clientCredential": {
"clientSecretSettingName": ""
},
"openIdConnectConfiguration": {
"wellKnownOpenIdConfiguration": "https://.b2clogin.com/.onmicrosoft.com/v2.0/.well-known/openid-configuration?p=B2C_1_Default"
}
},
"login": {
"nameClaimType": "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name",
"scopes": ["openid"],
"loginParameterNames": []
}
}
}
}
},
"navigationFallback": {
"rewrite": "index.html",
"exclude": [
"/images/*.{png,jpg,gif}",
"/css/*"
]
},
"mimeTypes": {
".json": "text/json"
},
"routes": [
{
"route": "/login",
"rewrite": "/.auth/login/AzureB2C"
}
]
}`