35mm color-skopar not locking proprerly on r2,help?

[perjohan]

recently my 35mm color-skopar lens fell off my bessa r2 while focusing.now when i try to put it back on it wont lock in as it should.
please any ideas or tips?

 

[pvdhaar]

Is it the screwmount Skopar with an adapter, or the M-mount one?

 

[Spyderman]

If it's the screwmount version: do you have a quality Leica or Voigtlander adapter ? The cheap no-name ones can be poorly machined and not fit well...