Why am i receiving OTP messages but being redirected to a 405 page in WSO2 IS?

I am trying to acheive two-factor authentication. The first login step should prompt the user to enter: username & password then SMS OTP for the second step.

The problem is that after configuring the SMS OTP, i am shown a 405 error after clicking the 'send OTP button'

This is the link of the page with the 405 error https://localhost:9443/smsotpauthenticationendpoint/smsotp.jsp?client_id=fJsj8UV4QEH5yWkuLjevFruYGyMa&commonAuthCallerPath=%2Foauth2%2Fauthorize&forceAuth=false&passiveAuth=false&redirect_uri=http%3A%2F%2Flocalhost%3A8080%2Fpickup-dispatch%2Foauth2client&response_type=code&scope=openid+internal_application_mgt_view&tenantDomain=carbon.super&sessionDataKey=cc73a6e6-168d-40ce-8003-c0c2a26afa16&relyingParty=fJsj8UV4QEH5yWkuLjevFruYGyMa&type=oidc&sp=pickup-dispatch&isSaaSApp=false&multiOptionURI=%2Fauthenticationendpoint%2Foauth2_login.do%3Fauthenticators%3DEmailOTP%253AGmail%2BOTP%253BSMSOTP%253ASMS%2BOTP%253Btotp%253ALOCAL%26response_type%3Dcode%26type%3Doidc%26tenantDomain%3Dcarbon.super%26client_id%3DfJsj8UV4QEH5yWkuLjevFruYGyMa%26relyingParty%3DfJsj8UV4QEH5yWkuLjevFruYGyMa%26passiveAuth%3Dfalse%26isSaaSApp%3Dfalse%26commonAuthCallerPath%3D%252Foauth2%252Fauthorize%26scope%3Dopenid%2Binternal_application_mgt_view%26forceAuth%3Dfalse%26sessionDataKey%3Dcc73a6e6-168d-40ce-8003-c0c2a26afa16%26redirect_uri%3Dhttp%253A%252F%252Flocalhost%253A8080%252Fpickup-dispatch%252Foauth2client%26sp%3Dpickup-dispatch&authenticators=SMSOTP

I modified the deployment file by adding the following.

### SMS CONFIGURATION ###
[authentication.authenticator.sms_otp] 
name ="SMSOTP"
enable=true

[authentication.authenticator.sms_otp.parameters]
SMSOTPAuthenticationEndpointURL= "/smsotpauthenticationendpoint/smsotp.jsp"
SMSOTPAuthenticationEndpointErrorPage= "/smsotpauthenticationendpoint/smsotpError.jsp"
MobileNumberRegPage = "/smsotpauthenticationendpoint/mobile.jsp"
RetryEnable = true
ResendEnable = true
BackupCode = true
SMSOTPEnableByUserClaim = true
usecase = "local"
secondaryUserstore = "primary"
SMSOTPMandatory = true
SendOtpToFederatedMobile = false
federatedMobileAttributeKey = "mobile"
CaptureAndUpdateMobileNumber = true
SendOTPDirectlyToMobile = false
redirectToMultiOptionPageOnFailure = false
TokenExpiryTime = 12

My SMS provider is using a GET Request and in all the documentation SMS providers use POST. Could that be the issue?

this is my Identity provider configuration for SMS

I also could reproduce the issue in IS-6.1.0 pack when the deployment.toml configs were added as mentioned. Remove all these configs from the deployment.toml file and try the flow. The flow will work properly.

### SMS CONFIGURATION ###
[authentication.authenticator.sms_otp] 
name ="SMSOTP"
enable=true

[authentication.authenticator.sms_otp.parameters]
SMSOTPAuthenticationEndpointURL= "/smsotpauthenticationendpoint/smsotp.jsp"
SMSOTPAuthenticationEndpointErrorPage= "/smsotpauthenticationendpoint/smsotpError.jsp"
MobileNumberRegPage = "/smsotpauthenticationendpoint/mobile.jsp"
RetryEnable = true
ResendEnable = true
BackupCode = true
SMSOTPEnableByUserClaim = true
usecase = "local"
secondaryUserstore = "primary"
SMSOTPMandatory = true
SendOtpToFederatedMobile = false
federatedMobileAttributeKey = "mobile"
CaptureAndUpdateMobileNumber = true
SendOTPDirectlyToMobile = false
redirectToMultiOptionPageOnFailure = false
TokenExpiryTime = 12