The specified XML cannot be pars to type Integer is not valid How can i solve this error

"The specified XML cannot be pars" to type 'Integer' is not valid - How can I solve this error?

The 'meta' start tag on line 9 does not match the end tag of 'head'. Line 10, position 3. Conversion from string "The specified XML cannot be pars" to type 'Integer' is not valid. Root element is missing.

The message appears when HMRC server is responding to the submission attempt using incorrect format. Close the submission process and attempt to resubmit the returns a few minutes later.