Address issue - unable to register for self-assessment

I am unable to register for self-assessment as the address on my registration form does not match with that on the personal tax account. When I tried to investigate why, the only possible reason is that while registering for self-assessment, the form does not allow dot to be input as a character. My address has a "St." in it, and while the personal tax account displays "St.", I have to write it as "St" in the registration form, which creates a mismatch. What should I do in order to register for self-assessment in time?

Hi Masha Manja,
Please contact our Online Services Helpdesk here for help and resolving this issue:
Technical support with HMRC online services
Thank you.