amazon web services - AWS Cognito Update user login issue in iOS -

i working on aws cognito login. works fine in cases such signup, signin, forgot password etc. edit profile case, facing technical problems. edited mobile number successfully.

in 1 of case provide wrong number , throws error this,

[awsjsonresponseserializer responseobjectforresponse:originalrequest:currentrequest:data:error:] | response body: {"__type":"invalidparameterexception","message":"invalid phone number format.”}

i using set of code update profile,

[[user updateattributes:@[attributes]] continuewithsuccessblock:^id _nullable(awstask<awscognitoidentityuserupdateattributesresponse *> * _nonnull task) {             //success             return nil;         }]; 

it provides success responses. failure responses not coming inside block. can me how failure messages in this. tried many ways still troubling proper solution. appreciated. thanks.