Error at merging Accounts

Hi All,

CRM 13 On premises.

I'm having a problem trying to merge two Accounts, after seeing the logs I can see an Error that use to appear several times(9 to be exact):

Could not load file or assembly 'microsoft.crm.sqlclr.helper, Version=6.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. An error relating to security occurred. (Exception from HRESULT: 0x8013150A)

Any reasons of why this could be happening?