Inclusion Criteria:  Ages 21-65 (inclusive) Seeking treatment to reduce or discontinue current cannabis use (smoke/vape/ingest) Current Cannabis Use Disorder per DSM-V (MINI for DSM-V) K10 score 10-35, inclusive (mild to high moderate distress) Definite MS diagnosis, relapsing remitting (RRMS) subtype PDDS score 0-7 (mild to moderate neurological disability, established to be able to complete procedures) All medications stable for ≥ 1 month prior to enrollment and throughout the trial Ability to understand the informed consent process and provide consent to participate in the study Stable and continuous access to internet service, email (WiFi "hotspot" to be provided if needed) Ability to use mobile devices Fluent in English language (due to outcomes validated in English versions only) WRAT-4 score ≥ 85  Exclusion Criteria:  MS clinical relapse or use of high dose of steroids in the past month Patients under medical marijuana use prescribed by a clinician Alcohol, tobacco, or substance use disorder other than cannabis Primary neurologic, psychiatric or other medical disorder other than MS (entry MD screening) Currently meets DSM-V criteria for moderate or severe substance use disorder in the past 6 months for any psychoactive substance. Meets DSM-V criteria for current panic disorder, obsessive-compulsive disorder, post-traumatic stress syndrome, bipolar affective disorder, schizophrenia, dissociate disorders, and any other psychotic disorder or organic mental disorder Current suicidal ideation or deemed to be of potential risk of self-injury History of traumatic brain injury Seizure disorder or recent (<5 years) seizure history Metal implants in the head or neck Enrolled in group or individual therapy for substance use disorder concurrent to intervention Any skin disorder or skin sensitive area near stimulation locations Pregnant or breastfeeding