diff --git a/src/common/mint-utils.ts b/src/common/mint-utils.ts
index a0cb354..8d8c3af 100644
--- a/src/common/mint-utils.ts
+++ b/src/common/mint-utils.ts
@@ -24,19 +24,10 @@ export async function dataNFTDataStreamAdvertise(
         dataNftStreamUrlEncrypted: data.encryptedMessage
       };
     } else {
-      throw new Error('Issue with data marshal generate payload');
-      // throw new ErrFailedOperation(this.dataNFTDataStreamAdvertise.name);
+      throw new Error('Issue with data marshal generating payload');
     }
   } catch (error) {
     throw error;
-    // if (error instanceof Error) {
-    //   throw new ErrFailedOperation(
-    //     this.dataNFTDataStreamAdvertise.name,
-    //     error
-    //   );
-    // } else {
-    //   throw new ErrFailedOperation(this.dataNFTDataStreamAdvertise.name);
-    // }
   }
 }
 
@@ -54,7 +45,6 @@ export async function storeToIpfs(
     res = await nftstorage.storeDirectory(dir);
   } catch (error) {
     throw error;
-    // throw new ErrFailedOperation(this.storeToIpfs.name);
   }
   return {
     imageOnIpfsUrl: `https://ipfs.io/ipfs/${res}/image.png`,
diff --git a/src/minter.ts b/src/minter.ts
index a59aa13..1382dd8 100644
--- a/src/minter.ts
+++ b/src/minter.ts
@@ -83,7 +83,8 @@ export abstract class Minter {
       return new BooleanValue(returnValue).valueOf();
     } else {
       throw new ErrContractQuery(
-        'Error while retrieving the contract pause state'
+        'viewContractPauseState',
+        returnCode.toString()
       );
     }
   }
diff --git a/src/nft-minter.ts b/src/nft-minter.ts
index 599b9cc..810a142 100644
--- a/src/nft-minter.ts
+++ b/src/nft-minter.ts
@@ -25,7 +25,11 @@ import {
   storeToIpfs
 } from './common/mint-utils';
 import { ContractConfiguration } from './interfaces';
-import { ErrArgumentNotSet } from './errors';
+import {
+  ErrArgumentNotSet,
+  ErrAttributeNotSet,
+  ErrContractQuery
+} from './errors';
 
 export class NftMinter extends Minter {
   /**
@@ -206,10 +210,6 @@ export class NftMinter extends Minter {
 
     if (!allPassed) {
       throw new Error(`Params have validation issues = ${validationMessages}`);
-      // throw new ErrFailedOperation(
-      //   this.mint.name,
-      //   new Error(`params have validation issues = ${validationMessages}`)
-      // );
     }
     // E: run any format specific validation...
 
@@ -220,11 +220,6 @@ export class NftMinter extends Minter {
       await checkUrlIsUp(dataMarshalUrl + '/health-check', [200]);
     } catch (error) {
       throw error;
-      // if (error instanceof Error) {
-      //   throw new ErrFailedOperation(this.mint.name, error);
-      // } else {
-      //   throw new ErrFailedOperation(this.mint.name);
-      // }
     }
 
     let imageOnIpfsUrl: string;
@@ -257,11 +252,10 @@ export class NftMinter extends Minter {
       metadataOnIpfsUrl = metadataIpfsUrl;
     } else {
       if (!traitsUrl) {
-        throw new Error('Traits URL is required when using custom image');
-        // throw new ErrArgumentNotSet(
-        //   'traitsUrl',
-        //   'Traits URL is required when using custom image'
-        // );
+        throw new ErrArgumentNotSet(
+          'traitsUrl',
+          'Traits URL is required when using custom image'
+        );
       }
 
       await checkTraitsUrl(traitsUrl);
@@ -459,10 +453,10 @@ export class NftMinter extends Minter {
       };
       return contractConfiguration;
     } else {
-      throw new Error('Error while retrieving the contract pause state');
-      // throw new ErrContractQuery(
-      //   'Error while retrieving the contract pause state'
-      // );
+      throw new ErrContractQuery(
+        'viewContractConfiguration',
+        returnCode.toString()
+      );
     }
   }
 
@@ -486,12 +480,7 @@ export class NftMinter extends Minter {
       );
       return addressesWithTransferRole;
     } else {
-      throw new Error(
-        'Error while retrieving the addresses with transfer roles'
-      );
-      // throw new ErrContractQuery(
-      //   'Error while retrieving the addresses with transfer roles'
-      // );
+      throw new ErrContractQuery('viewTransferRoles', returnCode.toString());
     }
   }
 
@@ -515,12 +504,10 @@ export class NftMinter extends Minter {
       );
       return addressesWithUpdateAttributesRole;
     } else {
-      throw new Error(
-        'Error while retrieving the addresses with update attributes roles'
+      throw new ErrContractQuery(
+        'viewUpdateAttributesRoles',
+        returnCode.toString()
       );
-      // throw new ErrContractQuery(
-      //   'Error while retrieving the addresses with update attributes roles'
-      // );
     }
   }
 }
diff --git a/src/sft-minter.ts b/src/sft-minter.ts
index 99604fb..43b2db1 100644
--- a/src/sft-minter.ts
+++ b/src/sft-minter.ts
@@ -28,6 +28,7 @@ import {
   dataNFTDataStreamAdvertise,
   storeToIpfs
 } from './common/mint-utils';
+import { ErrArgumentNotSet } from './errors';
 
 export class SftMinter extends Minter {
   /**
@@ -44,8 +45,6 @@ export class SftMinter extends Minter {
     );
   }
 
-  // [TO DO] Initialize the contract for sft minter
-
   /**
    * Creates an initialize contract transaction for the contract
    * @param senderAddress The address of the sender, must be the admin of the contract
@@ -202,10 +201,6 @@ export class SftMinter extends Minter {
 
     if (!allPassed) {
       throw new Error(`Params have validation issues = ${validationMessages}`);
-      // throw new ErrFailedOperation(
-      //   this.mint.name,
-      //   new Error(`params have validation issues = ${validationMessages}`)
-      // );
     }
     // E: run any format specific validation...
 
@@ -216,11 +211,6 @@ export class SftMinter extends Minter {
       await checkUrlIsUp(dataMarshalUrl + '/health-check', [200]);
     } catch (error) {
       throw error;
-      // if (error instanceof Error) {
-      //   throw new ErrFailedOperation(this.mint.name, error);
-      // } else {
-      //   throw new ErrFailedOperation(this.mint.name);
-      // }
     }
 
     let imageOnIpfsUrl: string;
@@ -231,13 +221,10 @@ export class SftMinter extends Minter {
 
     if (!imageUrl) {
       if (!nftStorageToken) {
-        throw new Error(
+        throw new ErrArgumentNotSet(
+          'nftStorageToken',
           'NFT Storage token is required when not using custom image and traits'
         );
-        // throw new ErrArgumentNotSet(
-        //   'nftStorageToken',
-        //   'NFT Storage token is required when not using custom image and traits'
-        // );
       }
       const { image, traits } = await createFileFromUrl(
         `${this.imageServiceUrl}/v1/generateNFTArt?hash=${dataNftHash}`,
@@ -256,11 +243,10 @@ export class SftMinter extends Minter {
       metadataOnIpfsUrl = metadataIpfsUrl;
     } else {
       if (!traitsUrl) {
-        throw new Error('Traits URL is required when using custom image');
-        // throw new ErrArgumentNotSet(
-        //   'traitsUrl',
-        //   'Traits URL is required when using custom image'
-        // );
+        throw new ErrArgumentNotSet(
+          'traitsUrl',
+          'Traits URL is required when using custom image'
+        );
       }
 
       await checkTraitsUrl(traitsUrl);
diff --git a/tests/minter.test.ts b/tests/sftminter.test.ts
similarity index 100%
rename from tests/minter.test.ts
rename to tests/sftminter.test.ts