I have a problem with gantry 5.5 - it brokes my site: https://www.triathlondamme.be/

I must restore my backup, but every time i use the gantry 5.5 - the site is not available anymore

Error: An exception has been thrown during the rendering of a template ("CSS Compilation on file 'lawyer.scss' failed on error: Incompatible units px and rem.: line: 33, column: 3 Call Stack: #0 import templates/it_lawyer/scss/lawyer/_footer.scss templates/it_lawyer/scss/lawyer.scss on line 97 #1 import templates/it_lawyer/scss/lawyer.scss (unknown file) on line 1").: An exception has been thrown during the rendering of a template ("CSS Compilation on file 'lawyer.scss' failed on error: Incompatible units px and rem.: templates/it_lawyer/scss/lawyer/_footer.scss on line 33, at column 3 Call Stack: #0 import templates/it_lawyer/scss/lawyer/_footer.scss templates/it_lawyer/scss/lawyer.scss on line 97 #1 import templates/it_lawyer/scss/lawyer.scss (unknown file) on line 1").