Power BI rest API : can not connect to "http" datasource

Hi
I am using below api call to update crendentials on my odata datasource 
https://learn.microsoft.com/en-us/rest/api/power-bi/gateways/update-datasource#basic-credentials-example

It is working fine when I used it for "https://" but its giving below issue when I am trying to connect for "http"

{"code":"DMTS_InvalidEncryptionAlgorithmError","pbi.error":{"code":"DMTS_InvalidEncryptionAlgorithmError","parameters":{},"details":[],"exceptionCulprit":1}}.

then I used 
aCredentialsMap= "{\"credentialData\":[{\"name\":\"username\",\"value\":\"" + credentialsArray[0] + "\"},{\"name\":\"password\",\"value\":\"" + credentialsArray[1] + "\"}]}";

body = Map.of("credentialDetails", Map.of( //
"credentialType", "Basic", //
"encryptedConnection", "Encrypted", //
"encryptionAlgorithm", "RSA-OAEP", //
"privacyLevel", "None", //
"useEndUserOAuth2Credentials", "False", //
"credentials", aCredentialsMap);

[DEUTranslation 1]-(PBIR_0009)Publishing the PowerBI file failed. Error code: {"code":"UnknownError","pbi.error":{"code":"UnknownError","parameters":{},"details":[]}}."

which credentialType should I use?

do I need to encrypt credentials? 

any help can be appriciated.